I'm Not Sure If I'm Pregnant. I'm On The Pill

I'm not sure if I'm pregnant. I'm on the pill but do not have the usual break every month. I had unprotected sex 2 weeks ago and recently I've had lower back pain, mild period type cramps, leg and hip ache (how ever I don't know if this is growing pains) and it's really worrying me. I've had sex since that as well.