Painful Sex

Sometimes when my partner and I have a lot of sex consistently many times a day for a few days.. I get very sensitive to the point that it's painful to have sex for a few days. It feels like a knife is being rammed into me. Even when we're not having sex, I'm going about normal life it hurts more on the outer lips. Is this just from too much sex in a short period of time or something more serious?? 😬