Please help me not freak out

I had sex on the 31st but it wasn’t for that long and he pulled out but this is my only second time having sex and since it wasn’t with a condom I had this brown ovulation come out hours later the next morning he got me a plan b and I felt the same side effects I had taking it the first time which was just feeling a little headache, and I’m just wondering if the plan b causes me to get my period late , I’ve been very stressed out lately so I think that’s also affecting my period this is only my second time taking a plan b as well.

I really don’t wanna be pregnant and have no one to talk to about this