Scared I might get pregnant

This weekend was my boyfriend’s birthday and we decided to get a hotel room to celebrate.My boyfriend and I have had sex before but we’ve always made sure he pulls out.For his birthday I decided maybe we could actually have fun till the end and not have him pull out.So I bought a gel spermicide that I put in before sex,but I’m terrified of getting pregnant right now I’m 21 and in college my mom has threatened me with kicking me out if I get pregnant and his mom isn’t supportive either.I’m buying plan b to make sure but I’ve read if you weigh over 150 the pill won’t work.I’m a bigger girl who weighs more then that and my period are extremely irregular I’ve been told I might have PCOS.idk what else I could do to make sure I don’t end up pregnant.I know Letting him finish inside was a stupid idea.Help?