Cyst?

So Monday I had sharp pain that hit me out of nowhere. It subsided and went down to more of a constant dull ache since then. I got tested and no infections, normal white blood cell count. My dr is pretty confident I have corpus letuem cyst.. Said it should go away. I didn't have an ultrasound, because with insurance it was still $650. Can't fork that over right now.. I'm scared, because I've read it can twist and cut off blood supply to the ovary. Or that it gets so big the ovary has to be removed. I'm also in my TWW right now. Ugh! Anyone dealt with this before?