what could this be ...

so ovarian cysts and fibroids run in my family... my mom had em, my aunt, and my grandma. and now that i’m almost 18, my periods have become extremely irregular. some coming in 10-16 days later than expected, AND my cramps have worsened to the point where i can’t move a certain way without feeling like someone is trying to rip my uterus out. i’m starting to think i MAY have either one of those things but my mom believes it’s just because of “weight gain”... and when i went to my doctor and spoke about it she recommended birth control but went off topic criticizing me about being “too fat for my height” but my body is pretty proportional, i don’t look “obese” or overweight.

but every time i try and lose weight i can’t or i only lose like two pounds but gain it back the next day.

any ideas on what this could be? hormonal stuff, dangerous stuff, being overweight stuff.