pregnant?

The last time I was sexually active was on dec. 1, 2007 and we didn't use protection. I don't know if he came inside me because he was kinda out of it because he had taken some medicine for a cold he was catching. 2 weeks later I still hadn't got my period but I  had this light brown discharge, it only came for like 3 days and then it went away. January and still didn't get my period, I was getting some lower stomach cramps thinking it was my period but it wasn't. On Jan. 14, 2008 I was supose to get my period but nothing only a brown discharge that lasted 2 days, 2 weeks later the same thing happened. Now in February i've had some light pink discharge and some lower stomach cramps also i've been getting bloated ever sence January. Some time during the mid of Feb. I went to the bathroom and whiped my self and had like a very very thin like of blood so I though it was my period that was about to come so I waited and waited. It's now February 27, 2008 and still no period! I still get cramps lately no discharge jsut alot of wierd pains, my breast don't really hurt only on the top and my nipples are a little sensitive but that's about it. Can I be pregnant?!?!?! Please HELP!!