The Pill

kaitlyn
soooooo story time.....
my Boyfriend and i had sex on july 1st and 2nd. Both times we used protection but the first time it slipped off completely inside me, he caught it before he came but we stopped and immediately went and bought the pill. The second time the condom slipped off again and it was just sticking out slightly, he came and i was freaking so we purchased the pill again. My period is due tomorrow and I was just wondering
1. how badly will this screw up my period cycle
2. how can we prevent this happening again, they have always been the same condom size and brand