Am i pregnant???

Okay I had unprotected sex in October. I had protected sex in November, he didn't cum either. I had my period in December but it was real light. Then I didn't in January. I did in February but the blood was kinda brown. My mother was six months along and had her period before she found out she was pregnant. I have gained 20 lbs and I am a lot more hungry than usual and can't sleep at night. I sleep best during the day. I crave chocolate a lot. Could I be pregnant? What should I do?