W T F

Okay, so about 5 weeks ago my boyfriend and I had sex and he ask me he was about to cum if I wanted to keep going or if it was okay to finish but I asked him to keep going until I told him when to cum but he didn't cum as much as he normally does. We had sex like 4 times in a whole week and sometimes we checked if it was his cum or mine but I thought it was mine. After that week he left back to his family (He came to visit me for our anniversary) and I started having pregnancy symptoms so I took many test and came out negative. Why did I get symptoms when I'm not even pregnant? We were always protected and used condoms. I'm not on any type of birth control what so ever. What's going on with me? Please help!