Whenever I run or do any form of cardio on the machines etc., that night and the following day I have terrible stomach pains, spasms and then extreme sensitivity to cold and heat. I will break out in sweats because i'm so hot and then will be freezing 10 minutes later. I notice that i do not have this reaction when i go a few days without intensive cardio. I am 5'4, 26 years old and about 109lbs. Any suggestions?