PP chances of pregnancy

I am almost 9 weeks postpartum and my husband and I had sex at 7 weeks 5 days postpartum and used the pull out "method". I got my period the next day for the first time since having my baby. My period only lasted 3 days and was very light when they've always lasted 7 and are heavy. I've been very nauseous lately and just want to know if I could possibly be pregnant? Can you get pregnant if your period comes the next day? Can you get pregnant this close after having a baby? And would I even be experiencing symptoms like nausea this soon if I even was pregnant?