I have had 2 lots of cysts that I know of when I was 15 and 16. The first time to dr thought my appendix was going to burst so had emergency surgery that that only to find out that I had an ovarian cyst that had burst.

Second time I had a lot of the same pain and had a u/s one day and surgery to remove it the next. They also had to take a small part of my ovary.

Both times i had strong painkillers beforehand and used wheat heat packs.

I think if it was serious the US place would have got back to your dr asap. I think cysts are fairly common and not always a problem.

Hope you get good news on Monday.