You are very probably dealing with adrenal fatigue and exercising with fatigue is NOT a good idea. If you haven't done the 24hr cortisol saliva test (do the comprehensive if you can afford it that checks the sex hormones too) you should do it.
EDIT: Forgot to mention it would be a good idea to get the labwork run that Janie recommends on her website too. You very well could be dealing with hypothyroidism (EVEN if your doc says your TSH is fine!), not to mention low ferritin and b12 which all cause fatigue.