Please help me I want to know if im pregnant!?

Ok well me and my 15 year old boyfriend had sex about 3 months ago on March 23 and I havent gotten my period. I am so scared because im a few years younger than him. Also my parents dont know he's 15 they think he's my age. He smokes weed and that is verry disapproving in my family. And that night we had sex we were high and dident really know what we were doing. We woak up the next morning and we were naked and their was a condom and everything so we know we did it. (My parents were out of town and he said he stayed at his friends house). And he broak up with me in June and dosent know that I havent had my period. I am so scared and I havent felt myself I've beensick to my stomache. Boobies are sore/ tender. Eating ALOT more than usual. And have been getting a rounder looking stomache. And no I am not a troll this is a serious question. And also I cant buy a pregnancy test because I dont have money nor can I drive so my parents would find out if I did buy one. And if you think that I am then can you tell me how to tell my parents about this.