Pregnant?

So last Sunday my boyfriend and I had sex and he said he had got off and I was almost completed with my period. I am on birth control but don't take it at same time everyday and I still have a chance of getting pregnant on birth control becaose all of my siblings and i are all birth control babies. The last few days I have been extremely tired, had massive headaches, and i had a hard time putting on jeans that are normally big on me the last few days. And I also don't gain weight and never have been bloated. And my cycle doesn't come again til 12/8/14