Late period.

So I was supposed to get my period on the 7th, but it didn't come. On the 7th, and the 8th I had a little light brown discharge, but nothing since then. I've also had cramps, and sore breasts. I had sex on the 24th of August using the pullout method, and I don't think anything went inside, but I'm not sure, and I'm scared to take a test I don't know what to do.