I have hypothyroidism and I am on Depo-Provera I exsercie 6 times a week and still not losing weight I used to weigh 135 now I am 166 im 5'3 and almost 21?

See detailed answer. Depo Provera (medroxyprogesterone) can be associated with weight gain and so can hypothyroidism. Cut calories, continue to exercise, and make sure your thyroid testing is normal. If the weight does not start dropping then i would change to another form of contraception.
Change Birth Control. If you are also limiting your caloric intake, your next best step is to change birth control. Depo Provera (medroxyprogesterone) is known to cause weight gain, depression, hair loss, & irregular bleeding. Interestingly, the same symptoms you can find with hypothyroidism. Switch birth control (ocps, iud, nexplanon, etc) & get your thyroid levels checked. It just might do the trick. Take care.