Last week I got a real buzz when I finished week 5 which is a 20 minute run (or jog in my case). I just got back from week 6, 1st run, which on paper is a lot easier 5 mins then 8 mins then 5 mins again, I got to nearly midway through the 6mins and had to stop. I felt sick and hot and a dizzy. an hour later my face is still burning. It was like I hadn't done weeks 2 to 5. I can't understand, I feel really down about it. I am 40 with a heart condition but I'm not sure that's got anything to do with it. Did anyone else hit a wall where they couldn't go on?