How Soon Can One Become Pregnant After Surgical Abortion?

Hello,

I had a surgical termination on December 31, 2014. I was 13 weeks the day of the procedure. However my husband and I had unprotected sex today. Heinz sight is always 20 / 20, and I know it wasn't a smart decision, but I am worried about ovulating. What are the chances I could become pregnant so soon. I have a follow up appointment with OBGYN in 1 week. Should I consider using Plan B? Any and all information you can provide will be greatly appreciated. Thank you in advance

Amy