Nervous?

Okay, so, I got on birth control, the depo shot, because of really bad cramps, and also, I was getting into a relationship, and getting pregnant scares me so bad (I'm 19). But, 2 days before my 2nd shot was due... I had sex and the condom ripped. I'm getting ready this week or next week to take a pregnancy test.... but I'm really scared. I haven't been spotting or gotten my period yet, even tho it usually doesn't come till the end or middle of the month and its only the begining. With the shot before I was getting a lot of spotting tho... what's your guys opinions?? I'm sooo scared and nervous. it would be my luck to do everything NOT to get pregnant just to end up pregnant...