Am i pregnant or not?

ok me and my bf had we used a condom, 2 to be exact we were both afraid it would break, we checked before and after no break or leakage, it happened dec 2, my last period was nov 21 i think im suppose to start dec 21 sometimes it happens at the last part of the month, i have had no signs or symptoms of pregnancy, no vomiting or ne thing like that, all i feel is some nausea, lower back pain where my kidneys are and i have been under stress and im worryin if i am pregnant, my mom said if i was to get pregnant id be kicked out i have no where to go, i hope its just nerves, and my stomach has been bothering me, some cramps no cravings i feel bloated im so worried, i took a preg test a while back and it said not pregnant am i worryin over nothing or wat cause im going crazy and staying stressed may be the reason i feel like i do ne advice, my period has not come yet i hope it does, if it dont could it be stress thats causing it. im 21 if it helps hes 26