I'm training for the 10k morun in Cardiff in November. I've worked up to 8.5k but I'm finding it so hard 
not enjoying it at all and feel exhausted!! What am I doing wrong?? There are another two weeks to go until the race and I'm sure I'll manage it but I want to enjoy the experience not crawl over the finish line.
Sorry for the moan, just feeling a bit sorry for myself
First things first. Running is supposed to be about fun so don't lose sight of that at this stage. Well done for getting to 8.5K, that's brilliant and a fair old distance.
Now, let's take a look. Have you been doing too much? Kept within the weekly 10% rule? It's good to chill and reduce the mileage every now and again so now you could take a few days off running completely, do something different like swimming, cycling or even walking. Do some stretches and just enjoy your body and tell it it's done a fab job getting you this far!
Next time out make sure you've had a good night's sleep, have something light to eat, drink water and run very slowly. Slow will get you through. Aim to do 8.5K and if you feel ok go to 9K. Don't fret about doing the full 10K now. Even if you did nothing else now, you'd still be able to finish the 10K on race day. I promise! You'll be fab as you are for having run 8.5K.
When I started upping my distance I struggled like crazy. I thought I was doing everything right, I increased the distance like I was supposed to and I was still having trouble. The one thing I didn't factor in is that I am a slow runner. I don't have a problem with that but it is important to acknowledge that, if you are because you need a little more fuel. My 10km takes my nearly 1.5 hours, so I am out there for a 1/2 hour longer than the average runner. Longer runs need good fuel. I can run up to an hour without anything extra in my diet but as soon as I go over an hour more food fuel is needed. The good news if it your fuel that is out it sorts itself out very easily.
First of all, well done for supporting MoRun- it's an event very close to my heart. I'm sure the adrenalin of the day will carry you over the finish line. 
However, it's not good to feel exhausted all the time. Assuming you're not coming down with flu or some other lurgy, perhaps you're just overdoing it in your efforts to get to 10k. Make sure you don't exceed the golden rule of only a 10% increase in distance every week and don't make every run a hard run.
To give you an example from my running week, I did a quick Parkrun on Saturday, then set out to beat my 5k PB on Tuesday, so another hard run. Then yesterday I did a slowish 6k but that, on top of the other 2 hard runs, was too much for my poor ancient muscles. I ache like the devil today, despite soaking in a hot bath last night and using the foam roller. The moral of this story is too much over a short space of time. I should have done a gentle 3k yesterday, or not run at all.
Sometimes we need to do less to achieve more. Perhaps you're just trying too hard. Why not have a few days off to let everything recover, then try a slow 8-9k. If that goes well, then you'll be fine for the race and you can maybe slip in a quick 5k to boost your confidence. Also, it's just occurred to me, make sure you're well fuelled up before and after your longer runs to make sure you're not running out of energy.
Very best of luck with the MoRun. I'll be running in the Leeds race on the same day, I think
How long is it taking you do run the 8.5K? It could be that you're running at a pace that's too much for the distance. Alternatively, RFC has a really good point. If you're running for much more than an hour, unless you're one of the lucky ones (not like me), you will need to think about fuelling not just before you run, but during the run. When I'm on long runs, I start to take on energy (Shotbloks, but things like jelly babies will do) every half hour from the first half hour.
Good luck. I do hope you end up enjoying the day!
I know exactly how you feel, I was training alone for a 10k I ran in September, I seemed to reach a point where I just could not increase my distance without feeling totally exhausted and taking loads of walking breaks, I felt really dispondent. Then my brother took me on board and started coming running with me, we did the 10% increase each week and I was amazed at the difference running with someone else made to me, not only for the company to take your mind off what your actually doing, but for the pace. I think I was running much too fast on my own for my own ability and tiring myself out too quickly. We ran at a nice steady pace and the whole distance thing started to feel so much more doable! Also I agree with all above who mention fuelling, I have found that before each long run, I need to have a bowl of porridge and some toast with peanut butter on, I have this at least an hour before I run and It keeps me going the whole time, I also take water with me because I seem to dehydrate very easily causing me to feel quite headachy for the rest of the day.
I really hope all these bits of advice and personal experiences help you, I didn't expect to enjoy my 10K race as much as I did, and I'm sure that you will feel the same. Slow down and stop stressing, it will all come together I promise. 
Also you are anxious as you have a looming deadline. Anxiety will make your body tense up which is no good at all. So you have to chill. Take a few days off and do as has been suggested and go for a swim or lovely walk instead. Eat/hydrate yourself properly and get some sleep. If you can clear some space to go for a slow jog after that then all to the good. Run with no plan or goal, just a slow pootle for fun. When you've chilled a bit then you can resume your training programme but go easy. Don't overdo things before race day
If you can do 8.5 k now then you'll be fine on race day providing you prepare right. The other runners and race-day adrenaline will pull you round. It'll be a blast! You just wait and see!
I'm doing a 10k MoRun on 22nd. I've only ever ran 10k three times, the last one was in July. I'm unlikely to run further than 8k before then. I'm thinking adrenaline and atmosphere (plus a few shorter runs in the week before) will get me through
We'll be fine 🙈let us know how you get on
Sounds like you need a few days rest from training then you will be full of beans agIn to continue. If not could you be run down / anaemic etc as that can make you feel drained??
Don't worry. If you're at 8.5K you will EASILY do your 10K. The vibes on the day will carry you through. Remember to go slow. Don't thrash yourself over speed or time - the important thing is to get over the line. JuicyJu is right. Take a few days off and rest up. Clear the cobwebs of doubt away and then come back revitalised.
May I ask: are you still running four times per week?
Yes I've been running four times a week but have only done twice so far this week because I've been feeling so tired.
Thank you all for your helpful comments and suggestions. I find it so reassuring having your support and advice.
As usual you all speak words of wisdom. I think the problem may be that I'm not fuelling up properly for a long run and I'm trying to go too fast! I probably need to accept I'm a bit of a snail. But I'd rather be a snail and enjoy it!!
I think a few days rest may be sensible and then get back to it next week with proper preparation. I'm not sure where I'm going to keep the jelly babies - I'll have to work that out over the weekend
I did it!!!!!
I took on your advice - had two days off, ate a big pasta salad for lunch, had a bottle of squash on hand and a handful of sweets and went for it - SLOWLY. Happily managed 10k in 1.20. Feeling thrilled and not at all worn out. It's amazing how different two running experiences can be. Thank you for all uour help and support - it makes a big difference to me and my running experience
Excellent!! I'm so pleased for you. Now you can just concentrate on enjoying the big day 😄
Struggle
Seriously struggling ☹️
Struggling with breathing 
Week off, struggling to get back to it 
