Condom slipped off during sex

I just had my daughter two months ago and I'm freaking out... my husband and I had sex and we used a condom and when we were finished it was inside my vagina.. what are the chances I could be pregnant again? He thinks when he pulled out is when it came off and there was semen inside the condom and the other half was hanging outside my vagina. I also haven't started my period yet since having her, but what if I'm ovulating? Could there be a chance of becoming pregnant if the semen was inside the condom?