pregnant?

My boyfriend and I had anal sex. He had a condom on but not a very reliable brand (hygeia). I also take birth control and am very consistent on taking it everyday. However my birth control is very sensitive to time since it is such a low dose. He did not come inside of me, nor did he penetrate my vagina at all. He did touch my  vagina a few times with his penis though accidentally during anal. I'm scared I'm pregnant even though he had a condom on. Now I am experiencing like a period even though I'm not even close to my pills in my pack. Somebody help.