I Am A 16 Yr Old Grl N Hv Been

i am a 16 yr old grl n hv been detectd wd pcod.. as wl as thyroid.. doctor advisd me to reduce my weight..i am 60 n my ht is 5'2.. though i dnt look lyk a fat being bt jst d prblm is weight..how shud i reduce it coz i assure u my diet is vry less...its not coz of my diet.. n also i hv been prescribd elestra... is it a gud mdcn..n wat shud b my nxt action