I'm trying to lose 20lbs by next year. I don't really have any problems with working out but there are days when i can't workout because i feel so tired even though i haven't done anything strenuous. Just a few minutes ago, i was doing my step aerobics but i was already feeling so out of breath. I figured that it might be because my windows were closed but few minutes after i opened the window, i was still feeling tired. I still wanted to workout. I am determined to lose weight so i hopped on my stationary bike. I was only on the lowest gear for warmup but i still felt tired. I figured that i might have hypothyroidism but my mom said that it is unlikely because im sometimes energetic. I also have PCOS. I am 17 and i weigh 130lbs. Can my obgyn tell if i have hypothyroidism?