I just need to vent and some advice.

I am 27 weeks pregnant ... When I was about 8 weeks I found out my bf was on a dating site talking to women
When I confronted him he said he was just trying to make friends... Now I think that's all bullshit excuse my language , I was torn , it hurt me so bad , I found out through a friend who was on that dating site too ( she is single) she recognized him through pictures on my fb. 
I felt stupid , I felt betrayed , i felt like this baby didn't mean anything anymore . And I have had a hard time carrying so now that we had a miracle he went off and did that... Ever since then I can't help but wonder if he talks to other girls, I always doubt ... And sometimes I feel really bad cause I don't feel like my baby means anything .. 😰😢 am I over thinking things...?