I started bleeding during sex and it was a lot. There was no pain at all. I wouldn't have even known if it wasn't so much. I went to the doctor and I was tested for all the sti's that would cause this and all came back negative. No infections, no cancerous cells, nothing. Dr gave me some pills because she said it "could" be a yeast infection, which didn't give me much reassurance. I took the pills anyway just to be safe. But since she couldn't find an exact reason as to why this happened, I'm coming here. Never saw doctors much help to begin with. Fyi I've always had a very regular menstrual cycle. I wasn't due for another two weeks so I know it wasn't that plus it stopped after half an hour or so. I'm really nervous to have sex again because of this and i just want to know and understand why it happened.