I don't feel pregnant...

I'm 15 weeks pregnant and I don't feel any symptoms anymore. I even feel like my baby belly is shrinking. I was just at the doctor last week and everything was fine, but this whole pregnancy I have been terrified of having a miscarriage, I had one two years ago and thought I was ok until I got pregnant again. I can't let go of the fear of losing another baby. I'm sure I am just being paranoid, but I don't know what to do...