HELP ASAP

Okay so me and my boyfriend recently had oral sex (this was about a month ago) BEFORE he cummed he put his dick on me for a few seconds NOT in me. AFTER he did that he cummed and then we stopped to prevent anything from happening.... My period is supposed to start today and it hasn't and the month is almost over... am I pregnant? I am a teenager and I don't know what to do PLEASE HELP. I am also scared to buy a pregnancy test... any suggestions??? And please , AM I PREGNANT???