What could it be

I was having period like cramping and pressure doen below all last week and suddenly today it was gone. My last period was on Sept 27th and my positive opk on october 15th peak on october 16th. Had sex but he didn't finish inside due to having to leave for work. But we had sex again on the 22nd and he came inside. What could have been the cause of the period like cramps and pressure??? My boobs are still hurting but not as bad also period due tomorrow