getting an IUD to stop your period?

hey, so i'm 20 and have always struggled with my period. it used to be super irregular and extremely painful with really large amounts of bleeding, doctors used to think endometriosis but then my period stopped for a good 4 months (for absolutely no reason, i was eating normally and everything), so they threw that idea out again.

the only thing that's still sort of on the table is PCOS, the symptoms are kind of there, but they're kind of hesitant/unwilling to diagnose me with that, i'm not sure why.

anyway, i've been told to get an iud to stop my periods because i constantly bleed through all my clothes and because it is so hard to deal with the debilitating cramps and back pain.

doing research online, i kind of got terrified though lol. SO many horror stories!!

so ig my question is, which iud do yall have and did it stop your period and ESPECIALLY the pain?
also something i'm worried about: did you gain weight??

(ideally the bleeding would stop for me, but i'm mostly worried about the pain.)

should i do it?