Getting an iud in three hours I need help UPDATE

So I’ve never had an iud and my periods are already terrible. I have endometriosis and I heard it can make cramps worse. Is there anything I need to know or do before this appointment? I’m honestly scared but I can’t take any hormones and my long term boyfriend and I broke up 6 months ago and I’m ready for a change. Any feedback would be amazing. Thank you ladies!!

UPDATE:

Thank you so much all, I’m doing a lot better today, the insertion didn’t go as planned I guess. I was told I have an abnormally small cervix so it took 4x longer 😂. I’ve never felt pain like that. But thankfully the shakes and stabbing pain is gone after 6 hours.

It was my second day of my period and now it seems my period has stopped?? Is that actually a thing?