Thank you to everyone who replied to my previous post about having slept for 15 hours!
Yesterday I ran my first 30 minutes - didn't focus on anything except my friend's backside and checking how much longer til this hell was over! The last four minutes I trapped myself between three hills and grunted all the way up and all the way down - I sounded as though I was in labour shouting Oh My God! - but finally I hit the 30 minutes and held onto my neighbour's stinky brown bins for support (they really stank but I didn't care) and then did my five minute cool down. The pace was slower but I ran 4.35km and for the rest of the day I concentrated on not being hungry and drank two litres of water through the day - I'm not a thirsty person so tend not to drink much but thought I would make an effort considering what I put myself through.
Am I exhausted today - NO! Maybe it was about keeping the fuel tank full and maybe I was dehydrated, either way I'm pleased because now I'm raring to get to the end of C25K. I will keep an eye on the exhaustion and make sure I'm eating the right things and drinking enough, and I think those supplements can't do any harm - though the liquid form makes you less constipated than the tablets!
Once again thank you for your advice.