Debilitating periods w/ no help

Basically what the title said. and i've already been to a gynecologist and they made me sit in a cold room and wait for an hour to get an ultrasound, said they couldn't see anything wrong and said the only choice i had was birth control. I don't want to take birth control but my periods are so bad i'm bedridden for 2 days and cannot walk due to being extremely dizzy and my legs give out under me. I started taking iron and magnesium and they improved my periods but it was still so bad i had to leave class and was unable to do anything but cry in the nurses office. Also i get really shaky on my period and it's been extremely painful since i got it. Idk what to do and the gynecologist was pretty dismissive.