Help please

So on the seventh of this month me and my boyfriend had sex not realizing it was a 27% day and even though he pulled out I have a tendency to freak out anyway, we do usually use protection, that day was not one of those days, I did end up taking a plan b the next day and didn't worry about it, but here I am 5 days before my period is supposed to be coming and I have cramps and dark clots And I don't know what to think, I usually don't have very many clots and I don't really know what to think , it would be very helpful if someone could let me know like I should probably relax or if I could possible be pregnant even though the possibility is small.