Get some calcium and magnesium into your system. If you have some calcium tablets, that would be the best way to get some. Also, try and get some potassium (from bananas or eggs). You'll cramp up to you have an imbalance - probably was balanced before you exercised a lot. Anyway, get those elements into your body ASAP and then lie down for a bit - watch some TV, but just don't move for a bit, as moving provokes it (but you knew that
Hope it gets better, Lynne!