I'm so confused

I'm 18 years old and I recently had sex last week.. with a condom of course. This pass Tuesday I started to discharge a lot but I thought that was normal but yesterday my period came on and then after a few hours it went off. However! My period came on about 2 weeks ago. I'm so confused and stressed because i don't know what's going on with my body and I need help. Does anybody have a answer😩