Help! I'm confused...

I haven't had my period since November 26- Dec 1. I got a blood pregnancy test in January and it said negative. The hubby and I have had sex since then, but is it possible to ovulate without having a period? Or is it possible that I had a REALLY light period or something? I just took this pregnancy test for kicks because I don't know why I haven't had a period in so long and was curious....thoughts? It is positive, right? HELP!