Is it possible that I'm pregnant?

I took Plan B Onestep on February 18th and had my period a week later. It lasted for about 10 days. Today it is June 28th and I haven't had my period since then. I normally have irregular periods (2 or 3 months late sometimes). I'm very paranoid that I might be pregnant but I'm showing no signs except for sore breasts and the lack of period. I'm not nauseous, always hungry nor have I gained weight. I have a lot of discharge, though, typically seen while ovulating. I haven't taken any pregnancy tests yet. I'd like to think I'm PMSing because I was very emotional the other day. I also think my cycle is very late because of the PlanB, irregular periods and the fact that I exercise a lot. However, is it still possible that I might be pregnant?