please anyone, idk what to do

i didn't have unprotected sex this month and i know condom surely it didn't break. now, i have cramps and idk like nausea but it was only today and i had sort of heartburn.my breasts were fine as usual. i took the test and it was negative. i really don't know what to do, is this all in my head or something. my period is irregular so idk when it will come. does anybody know what that could be or am i tripping, because i do not want to be pregnant at this age. im 17 btw