someone PLEASE help me

I'm 14, and I had unprotected sex for the first time almost 3 weeks ago. I know what I did was wrong, and I should have used protection so all I'm looking for is advice! The sex lasted for at most 30 seconds, and the rest was oral. I never felt any cum nor did any come out afterwards. My period is supposed to be soon, but I'm still freaking out I will be pregnant. It was not during my fertile window, so what are the odds I am pregnant? What should I do?