On Sept 18 I Believe I Had My Period It

On Sept 18 I believe I had my period it was just spotting not heavy, very light. On Sept 24 I tried stopping my period since my partner was back from his trip. My period stop. That night we had intercorse and he came in me. We also did it again in the morning and he came in as well. But that day later on my period came heavy. 3 days later I had an appointment at the doctors, I usually take a plan b when he comes in me but this time I did not. I took a pregnancy test with my doctor and it came negative. The next day I started taking birth controls and on Oct 18 I stopped but my period has not come till this day and I have no signs that my period is coming. I have had wierd symptoms (like pregnancy symptoms) I wanna know is it possible that I am pregnant?