Scared!!!

Here is tha problem I had unprotected sex 3 times on the same night about 2 weeks before my period. I get a call about a week later from my bf sayin "oh you might be pregnant" I get my period and it only last about 3 day when its usually 5 days and its light, normally its really heavy. The day after my period I had unprotected sex again twice in 1 night which was the 10th of sept. Now all of a sudden im having all of these symptoms. Im having lower back pain, abdomen pain, my breast are kind of soar, and they look as if there gettin bigger. Im always hot, its like im having hot flashes or somethin but im only 17. And im starting to sleep more, I take a nap about 3 to 4 times a day for 3 or 4 hours each. Which is not like me to do. My sides hurt every night when I lay down, my breat bone hurts also. Like i'll eat when I think im hungry and then 30 minutes to and hr. Later, my stomach starts to hurt again like a hungry feeling. Whats that?? That doesnt happen to me. I cant lay on my stomach because its uncomfortable. Well to sum it all up im on birth control. I've been on them for about 4-5 months. But I hardly ever take them, im always missing pills, and I dont take them at the same time everyday. So what do yall think?? Could I be pregnant or whats going on. Oh yea and about 3 days ago I had like a white discharge, and today it was like brownish but it went away. So... I dont know!