Get my fiancee back after i made a mistake? Advice?

Im 29 and have been in a relationship with my fiancee for 8 years and have been engaged for 3yrs, she is 26. I am a firefighter and work shift hours and she has a full time job we also have a 6mth old son together, she suffered postnatal depression. I wanted to become a father for years and i adore him. My ex & i haven't been getting on that great since the birth of our son, She comes from a large very dysfunctional family who are alcoholic's but also work on the job, Many of her family can't keep a relationship or a marriage as they have all either left their partners or cheated on them, she never settled on a wedding date. She was really rebellious when i met her but she tries so hard to be the opposite of her family and worked really hard to get her career. Im in love with her so much but i couldn't stand the fighting and tension anymore, I've asked her to try counseling but she says we don't have the money and we don't need a third person sticking their nose in that we can work on this together. She is like her family, very stubborn and really hot headed, we have had arguments a lot and then she would break down crying saying she can't take this anymore and i try so hard to cheer her up. Two weeks ago at the firehouse i asked her to drop me in something i forgot and she brought the wrong thing and i told her she either had a 2 second memory/brain the size of a fish and she pushed me & told me to f*ck myself and left even, i tried to call her back. We broke up the next day as i thought it would be a wake up call for her but now she wont even speak to me and she moved out of our house to her brothers place, i never see her even when i pick up my son. I love her with all i am & i can't imagine life without her this all backfired on me, I need some opinions on what to do!?