What Do Delayed Periods With Cramps And Nausea Post Unprotected Sex Mean?

Hello, I recently had unprotected sex on the 6th day of my period (February 1st) and took Aftera emergency contraception 48 hours later. He only had precum. About a week after taking the emergency contraceptive I past blood and clots for five days. I have not had period since and I m worried because for the past three days I ve had menstrual like cramps, the slightest bit of nausea and breast cramps but no tenderness. Could it be just the EC? Or could I be pregnant?