Bleeding during sex?

On two occasions, I have had a lot of bleeding during sex. Both times I felt a lot of pressure, shortly follow by a really “wet” feeling and a relief of pressure... only to come to find that the wetness was a lot of blood. This bleeding both times has lasted most of the next day... has anyone else experienced this? Just went to the gyno last week and tested negative for gonorrhea and chlamydia. I had a pap and nothing showed abnormal..,, I’m still slightly concerned? The first time I thought it was just random but now that it happened again I’m worried.