Pregnant or freaking myself out?

Ok so I’m super scared and need tips/advice. So on Monday the 9th I had unprotected sex.. Mind you this was the very first time I’ve ever had sex and my dumbass let him do it with no condom.. I also am not on birth control, and my period was supposed to be starting sometime this week so I think I’m pretty fertile. It was a quickie so it didn’t last very long, but he did pull out and cum. I’ve been told you can still get pregnant from pre cum so that is what I’m worried about. On Wednesday the 11th I went and bought a Plan B. So far I’ve had no side effects, besides a small headache and cramps maybe 3 hours after I took the pill. After that, nothing. I’m constantly looking up how soon can I tell if I’m pregnant, is Plan B not working if there’s no side effects, how soon can I take a pregnancy test? I’m legit freaking out, because I’m in no state to take care of a child. I’m also young, and as you can tell obviously dumb. So if anyone out there can please take the time to maybe give me some advice or tips I would really appreciate it. My parents never really educated me on sex/pregnancy besides always telling me if I have sex I will get pregnant. So I’ve always been scared to have sex and now that I have I’m legit freaking out that I am pregnant.. I’m making myself sick thinking about this. I honestly feel I don’t know as much as I should, so please can someone give me some tips/advice or even educate me.