I’m 15 and I’m on the patch but due to some health issues doctors have told me they can’t confirm that it would prevent a pregnancy and I shouldn’t rely on it. So anyways exactly a week ago I had my first sexual encounter and we didn’t have a condom so I didn’t let him go in me however he did cum on my bum and we did some other things. I’m supposed to be on my period and I was getting the symptoms I usually get when that’s about to happen so I took off my patch expecting a period but it’s been 3 days wth no patch on and I haven’t gotten my period. I realize I’m probably just paranoid because it was my first time doing anything like this but I need reassurance

Could I be pregnant??? When do I need to start worrying?