HELP.

I've had two cycles. My periods were 5 days each. The first two days heavy, third medium, fourth light, and fifth light/spotting. I'm on the pill and have been for almost five months. I always use condoms except for one time my boyfriend put it in twice without one on. I've taken one test before my last period on March 28, started the 29th. It ended April 2nd. Taken three after the period. All four tests negative. Is there anyway I could still be pregnant? My boobs/chest have been warm to the touch and red but I'm currently having seasonal allergies. I'm extremely stressed out and upset over this. We have never had a condom break. He never ejaculates inside of me, even though we have a condom he still pulls out. He also had two undescended testicles when he was young and didn't get them fixed until he was about 8 years old. There is an extremely high chance he can't even have a child.  Everyone keeps telling me I am fine.  I don't want to be pregnant. I don't see how it is possible, but the internet keeps scaring me to death. I think I've actually scared myself into having symptoms. My next period is due April 26th.