CYST? COMING UP PERIOD? PAINFUL!

Anastasia
Okay so the last few weeks my stomach has been swelling like I'm pregnant but I haven't had sex in months (sadly) and I've been puking and not having control of my bladder. Uterous is in a lot of pain. I think it could be a cyst in my uterous or on my bladder. Or it could be my period coming up, but I've never had these symptoms or been in this pain.. please help