don't really know what to think..

So, my boyfriend and I have been ttc. I'm 17, in college and ready to start a family. (we've been dating for about 2 years.) he works for the railroad but, is home for two weeks every few months. We've had unprotected sex and he came inside me every time but I don't know if I could be or am pregnant. I've been sleeping more and getting dizzy but maybe that's just other things affecting me. I don't know though. I guess I'm asking for advice to see how I could get pregnant easier.? Thanks in advance!