I did my best on my lower body workout day. In fact, I had wobbly knees for a long time afterwards. I did my stretches, went back home, had my meals on time by the book. The following day, I could not run. I started my cardio with a walk, then a speed-walk for a minute. When the time came for me to jog, I had terrible pain all over my legs. I did my best and ran as fast as I usually do. I lasted 13 minutes then I had to stop. It was like my hamstrings, calves, quads, and shins turned into hot rods inside my legs. I had to go home. I did more stretches. Today my upper body workout went great. I am dreading my cardio tomorrow. I am not sure what happened. Did I do too much on my LB day? How do I know if I am not stretching enough? I stretch for 10-15 minutes and hold the stretch till it eases, or for a count of 20 seconds. What went wrong?

I don't do anything other than the treadmill for cardio as it seems to be the only thing that pushes me to the limit.

Thanks.

PS: I posted another thread about my cardio and lower body workouts. I think I know where the problem is coming from. I did not build up my workouts. I am just jumping into them. I will try to tone things down to a reasonable scaleable level otherwise I will get an injury again. Thanks for the answers.