I had a missed miscarriage, and I understand the level of concern you must be feeling, and the internal conflict as you tell yourself it's probably just 'normal' pregnancy symptoms while you wonder about the potential consequence of ignoring each and every twinge.
I'd love to be able to give you some sort of magical advice that will ease your fears for this pregnancy, but, honestly, I worried my way through to 20-odd weeks when I could feel my baby's movements on a regular basis. Best advice is to note your fears and concerns, take a deep breath, and move on with your day. And feel free to contact your midwife or GP with concerns - they'll understand!
I did loads of reading up on miscarriages, and a ridiculously high percentage of miscarriages occur because of chromosomal abnormalities. So something hasn't worked at the most basic level, which means that there is no chance for normal development. So, while it didn't lessen the grief, I found it comforting that losing the baby, while heartbreaking for me, was likely the best thing for the baby.
The hardest thing for me to deal with was the loss of trust in my body's ability to tell me what was going on. My first pregnancy, I was convinced something was wrong but ended up with a beautiful girl. My second pregnancy, i felt 'pregnant' and had moved into that lovely healthy pregnancy 'glow' but had a missed miscarriage which was not detected for four weeks. Then my last pregnancy I trusted absolutely no symptom, and almost didn't allow myself to believe the pregnancy would succeed, but I now have a lovely baby boy who is one month old today.
Just know that your fears and concerns are valid and normal. It's ok to feel excited one minute and pessimistic the next! And your fears will not influence the success of your pregnancy, or the well being of your child. So you just take good care of yourself, do all the things you should be doing (drink lots of water, take appropriate supplements, eat well and get lots of rest), and be very kind to yourself as you ride the emotional rollercoaster.
All the best