Coincidental?

A few weeks ago my bf and I were having sex, no condom and used the pull out method. I can't say for sure if there was any cum inside. But I felt like There was. Well the past 3 days or so I've been extremely tired, very nauseated, cramping, and have found most food repulsive. I'm not supposed to start until 1/23. I have a 14 month old, I sorta remember what I felt like when I was pregnant with him but I can't tell if it's a mind thing or not. Soooo thoughts?
On cycle day 32 btw