Please help....

I'm 20 years old. I have an 8 month old baby and I'm engaged to his dad. I was really great friends with his dad for years before we started dating it will be 2 years together in September. Were supposed to be getting married this October. I have everything. Hes sweet and supportive and an amazing dad and partner. But we dont have a connection. The spark fizzled after 6 months but I was pregnant and I'm a longtime relationship kind of person. Before my fiance I was with a boy for over 3 years. I have never really been single. We cant make it financially on our own. Neither of us have parents we were both foster kids. He says hes in love with me and I believe him. He tries so hard to make me happy but I'm just not. Maybe theres something wrong with me. I don't know what to do. I dont want my family to be torn apart. I want my baby to have what I never did. But I'm so unhappy it's like I cant breathe. I have no friends. I have no one. I just want to disappear.