Hi I'm 18 and I'm a little worried that I'm pregnant. I'm on the depo birth control so I had 3 months of protection that me and my boyfriend had sex during but after the 3 months i had a 4 week period which my boyfriend and i still had sex. It's been a couple of days after I got my second shot. Now I'm tired all the time, I get some cramps, I have lower back pain, I'm nauseous occasionally, and I feel hungry a lot, I'm moody, I get really bad headaches, my nipples are darker then normal and I'm irratated easily. I would really like some advice on this I dont know if its the shot or if I'm pregnant.