Hello, I Delivered My Baby About Two Months Ago But

Hello,

I delivered my baby about two months ago but I'm experiencing a problem that does not let me sleep. I had unprotected sex with my partner and somebody during the time I conceived. My last menstraul was November 12 and had unprotected sex November 29th and December 4th. I never talked to my OBGYN doctor about this because I work in the same facility and I feel ashamed. I would like to know if you can recommend a home paternity testing or if by the given dates you can kind give me an idea of who can be the father. I delivered the baby August 16th and the ultrasound stated I conceived December 4th. Also how accurate is an ultrasound with the dates? Thank you