Being overweight cause 53 day long period?

Ci
I started my period Sept. 9th and have been bleeding ever since. Oct 16 - 29th was bleeding so heavy I filed a super tampon every 45 mins. I've been to the doctor twice and the ER. All tests have come back fine. Ultrasound came back fine. Only answer my doctor can give is that my weight is why my period is messed and why I'm not ovulating and why we can't get pregnant. I am 300lbs and I know im overweight but I know bigger women who have no problem. Should I accept this answer or get a second opinion?