am i pregnant?????

i need serious help. im so scared. i am 15 and ive been with my boyfriend for 6 months now but im so scared that im pregnant. im not on any birthcontrol and i never regulate my period cycle or days. i just got this app like a month ago because i wanted to try to regulate my period more to keep track when i miss it or not but when i was entering my information i sort of just guessed on what i thought maybe was true like how long my cycle is and stuff and now its saying i missed my period and im having nausea and my boobs are hurting which is normal when i am getting or on my period but i heard thats also symptoms for pregnancy. im so scared to even take a test or ask my mom for a test because if it read yes i am pregnant i dont know what i would do. i am NOT ready, AT ALL to be a mother or give birth. pls, somebody help me, i need advice :(