I Need Advice I Think I Might Be Pregnant...

about a week ago i went to my bf's house and we started making out and he asked if he should put on a condom and i said yes and he put it on and he really didnt have it in so i just kind of faked it cuz i really didnt want sex and then he cummed and took off the condom and i started to suck on it and i got on him cuz he told me to and i 4got that he didnt have the condom on and i think stuff was at the tip when he put it in agian idk what to do im freaking out i cant tell my mom because she always calls me the "perfect child" because my sister gets drunk all the time and my brother is mentally challenged so thats alot of pressure on me and i cant wait till my period even thoo it should be happining i start any time from the 19 - 25 and sometimes i still skip a month i want to take a pregnancy test but idk if their is an age limit to buying them?it was the first time having sex then the next day he dumped me and went out with my best friend....what do i do please help