Is There A Chance?

I had sex on Jan 15th. And he ejaculated in me. Completely. Here's the thing though. I lost track of my menstrual cycle in October because I made a bad choice and took Plan B. But I THINK I am due to start my period or that I will be within the next couple days. I know that you have less of a chance of getting pregnant outside of ovulation. But what is the likelihood that I could be?