Needing Advice

Micah
So I had my son at the beginning of September (2016). I've had two periods since then, my next is supposed to start tomorrow, when we started having sex again some of the times we used condoms and some of the times used the pull out method. Well when I found out I was pregnant in January I spotted for one day a couple days before period was supposed to start (spotting stopped after the one day) but my period never came, I had the same exact spotting a couple days ago and today my breasts are sore. 
What are the chances of getting pregnant by pre cum? I'm starting to get nervous since my baby is only 3 months old. 
Please no harsh comments just trying to get some opinions.