I had no idea that i might be pregnant. scared. please help.?

I just recently got back from a week's vacation. During this vacation I drank alcohol heavily, smoked a lot of marijuana, and tripped on cough medicine (DXM). I know some of this is illegal and Im not asking for you to preach on how I shouldn't do it anyway, but I just came to the conclusion that there is a POSSIBILITY that I am pregnant. I have not missed my period yet but when looking at my calender I noticed that I had unprotected on 3 critical days during ovulation. I still have 2 weeks until my period is supposed to arrive but when I realized there is a possibility and remembered all of those damaging things I have done I started freaking out. If i am indeed pregnant and was probably pregnant during vacation what will happen to the baby? oh and FYI now that I know there is a possibility I have stopped doing everything listed above, im just nervous that my previous mistakes may have caused serious damage. :( please help.