I'm stuck

I've been dating someone for over a year now and I honestly can say we both have problems. In our third month we became pregnant with our first daughter. We have children separately from one another. She has two boys and I have a son. Her two sons are autistic and demand a certain type of care and attention. My daughter's being almost 7m needs a greater demand. I feel like I'm with someone who doesn't see me as a lover but, a father/babysitter. I found a new job doing agency(independent cna) and I can barley even work. She always over booking and it traps me in. I was in school and when ever I had class or tried to study she want my attention or acts as if she doesn't know how to be a parent. So I ended up failing that. When I want to go out with my boys it's a argument. She go for guilt tripping, my did that, and I told my lady I don't like that. An I've been trying really hard to make this work but I'm no longer attracted and feel drained with our conversation. All she dose is complain how other ppl hurt her and that nothing makes her happy. I've tried to help her but she always has a excuse. I can't even walk to the store to get beer with out her having a complaint or excuse why I shouldn't. It seems our maturity is in different worlds from each other.