pregnancy???

Okay, so like. I had Anal sex on April 10th. It was my first time and everything and he didnt know. Yadi yadi yadi Lol We used protection... but his dick was like 6inches. & the condom kept slipping off & stuff and he would stop to fix it and sometimes idk at one point i felt like he took it off but then when i looked back it was still on when he fixed it again. He didnt cum in me or anything because I swallowed. I havent had any other sexual contact lately. But now I'm 8 days late for my period & eve says theres a 7% chance of pregnancy. I can be irregular but it's literally been a month since my last period... So I'm like