Hi there...

A bit of background:

I'm Female, 45 years old and 5' 6" tall. Up until recently I weighed 110kg (around 248lbs) and am now down to 87.3kg (192lbs) so it's a 50lb weight loss to start with all from walking 5+ miles a day. I fractured a kneecap 15+ years ago and I used that as an excuse not to do things but in hindsight it was more likely the 110kg that was holding me back. Anyway... when I started to lose weight I said to myself that I would start running when I hit 80kg. Last weekend I had a bit of a think about it and started wondering if I really did need to wait until I was down to 80kg. The way I am going that would be another 2-3 months away.

Monday morning I went out for my first c25k run and I felt fine. My knee didnt hurt. I wasnt hugely out of breathe and I got through the entire experience relatively easily. Certainly more easily than I thought I would. To say I was happy about it would be an understatement. Here are the "run" details:  http://www.rundouble.com/?page=map/3141039/RVEGgG2735

So today I went out and did Week One Day Two and I totally struggled. I only managed to do 6 intervals rather than 8. I couldnt breathe. My legs felt like jelly. It was awful. I ended up walking from the end of R6 because I could barely get a breath. I dont think I pushed it at the beginning at all so I dont think that is it. I cant believe that I struggled that much. Here's the details of W1D2: http://www.rundouble.com/?page=map/3072014/YrSFCaNCrk

I dont think I did anything different between the days that should have made me be like that.

Any hints, tips, thoughts, comments would be most welcome because I dont understand why it was SO different from one day to the next. I dont intend to give up as I really want to do this but I want to try and understand why this happened.

Thanks in advance