Could I be pregnant?

My boyfriend and I got back together recently. We had sex on the 20th of January and the 26th. I have been on birthcontrol since November, so we didn't use any other protection other than pulling out. Since I have been on birth control, I have not had a period. I'm on my third month, first week. Recently I've been cramping, sore breasts, increased appetite, mood swings, urinating more, and friday I had brown stopping in my undies. I took a pregnancy test on Saturday, the 30th of January and it came out negative. I have no idea what to do!