Cysts

So, I went back to the doctor today and they're scheduling me for an ultrasound at the hospital later this week due to a pain in my lower side. She's concerned about that and the fact that I'm rather late on my period and not pregnant. Her concern is that it's a cyst on one of my tubes that's preventing an egg to come out hence halting my period. I get ovarian cysts that never really last that long, but this is much more painful that those :(