How do I increase my lost stamina again? Also why did my legs get heavier and how can I stop it?

Today I did the pacer and I passed by getting a 52 and stopped at 52 because I was actually starting to slow down even though I wasn't that tired and I'm really fast my legs just wouldn't move.(I know by headache which gave me a nosebleed and my hunger and thirst and the fact that I had a spasm this morning lasting 15 minutes which made my legs soar didn't effect this) I'm use to harsh training conditions.

How do I increase my lost stamina again? Also why did my legs get heavier and how can I stop it?
Your legs can feel heavy because of two different things. They could be over trained and need a few days off... or they could be more out of shape then you think. I know towards the end of my Cross Country seasons my legs start to feel very heavy and it is from over working them. That is why you taper towards the end of seasons. If it is because you are maybe just not in the shape you are use to being in, you just have to give yourself a few weeks with your normal training and they should start to feel better.
Reply:You musn't have had much work out in while. You just need your bosy to get used to being pumped up again, the muscle spasms should go away after a week of training.