strong pregnancy symptoms but periods and negative tests

I have no idea what's going on with my body.. my boyfriend and I had sex 3 times on my fertile days. Soon after that, I started experiencing pregnancy symptoms. Well, sex triggered my period into coming when it said it would. When I had my period, my symptoms stopped. My period was done a couple days ago and now I'm right back to having strong pregnancy symptoms. I've took multiple tests and it's negative and I had my period so there's no way I could be pregnant right?