Is there any chance I'm pregnant?

I last had sex two weeks ago, June 11 I think? My last period was May 19-25. My periods are rather irregular, and I've only had sex a few times. I haven't gotten my period yet, but I started spotting the other day, and now it's stopped and has subsided back into normal, not-on-my-period. I am getting really nervous about this, as I'm 17, can't support a child, and my parents will not let me get an abortion. I've been doing research on inducing your period using vitamin c, parsley, and the like, but I keep coming back to the possibility that there is a slim chance that I might be pregnant. As I said, my periods ARE irregular, but I'm still worried about this. We're 99.99% sure that the condom didn't break but still... I don't want to deal with this. Help please!!