Woke up bleeding.. what could it be?!

I woke up this morning and had to go to the bathroom. I was waiting for my fiancé to get done, sitting on the edge of the bed. Next thing I know it feels like I peed myself. I went to check and blood was everywhere. I'm not supposed to start my period for another 2 weeks, and I do have endometriosis. I'm in a lot of pain which is normal with my endometriosis, but this I different. It's higher up more towards my stomach and transferring to my back. I've never had any period like this, and I'm kind of freaked out. What could this be???