I have been doing C25K consistently for the past 2 weeks. Suddenly I'm at week 3 and it's really hard for me to get through 3 minutes of jogging. Day 1 &2 I cut the second time through a few seconds short because I just couldn't breathe. I'm a large person with weight to lose but not dieting just trying to eat healthy and drink more water. Sort of discouraged because week1&2 felt good. My legs hurt this week and I am whooped at end of "run" on week 3. Also I'm actually covering less distance on week 3 runs. Week 2 I had a pretty good Increase in distance. Should I forge ahead, or go back to week 2?