Im so depressed in this relationship, what should i do?

Ok here is my problem... I got my girlfriend pregnant when she was 16, and I was 17. I then rushed to get my high school diploma, and she got her ged. after we both got our diplomas we got married, and shortly after had our baby girl. One week after my daughter was born I left for basic training, ait, and airborne school for the army national guard. I have been home for 6 months now. Here is were the problems begin. I have been working Overnights at walmart busting my balls for the last 3 months. I work Overnights so my wife can go to college while I stay home and watch my daughter. Anyway money is so tight. We don't even have enough to pay for health insurance. We live in an apartment and every month is a constant struggle just to pay bills. Honestly I love my wife so much, but I am constantly doubting why we got married. I don't want to live like this anymore, but I don't want to completely screw my wife over by leaving because then the bills would fall on her, and I love her too much to do that to her. Another problem is her parental live so far away if she were to move with them, she would no longer be able to go to school because they literally live in the middle of nowhere. I on the other hand would just move in my parents basement about 45 minutes away, and transfer walmart. I want to be able to go to school and get my education, but I'm so tied down to my wife and child. I'm never happy with her, and things just aren't the way they used to be. I'm just so confused as to what's wrong and what's right. I'm confused as to what I should do. Please any input would really help.