Pregnant at 3 months PP?!

Hi there

I had my son 3 months ago. It’s been wonderful and both my husband and I agreed we want another one within a year or two. We have been having unprotected sex, occasionally using pull out method.

My problem is that I’m breastfeeding so I don’t know my cycle yet. It’s all out of whack. I’ve been experiencing (in this order): headaches, fatigue, slight cramping, and nausea. Today I noticed my boobs were a bit sore, but not from breastfeeding. I haven’t tested yet and I’m very scared to.

What are your thoughts? Could this be PMS?