2 months postpartum, chance of pregnancy again?

So I just had my son November 2nd 2016, I started my period December 22nd and it ended January 6th I believe (not too sure, it may have ended a day or 2 after but I don't remember all that well). Anyways, according to my period log I am in my "fertile window". Me and my SO were finally intimate for the first time last night and he did not pull out. I was just wanting to know how likely I am to get pregnant that soon after having my little guy almost 11 weeks ago.