late period

I don't know if I am pregnant I really feel like I am not. I had sex January 20th(during fertility) with a condom but I am 9 days late on my period. I didn't know if I should've been worried the day after I did throw up but I was hungover and I threw up alcohol and I run cross country so I do workout a lot but my periods are usually normal but the only other symptom I have is sore breast but I think it's because I am about to start my period anyone help advice please?
I'm 15 btw.