Help please!

👸🏻Mamasita💙👶🏻
I just a a really quick question. I just gave birth to my first son in Dec 24th 2015. I have had some light bleeding since then. Last night my husband and I had sex and he pulled out but I'm pretty sure some of it went in. What are the probabilities for me to get pregnant? I'm not seeking for it. So I just wanna know if I should take a pill or if I should not even worry about it.