If I have this right you bought with your ex, he has left, you are paying all mortgage? While you most definitely should see MABS you must also regularise your legal situation vis a vis the house. Otherwise I see you struggling( at the expense of your quality of life and that of your child) to repay mortgage and when the good times come back so will your ex looking for his 50 % share of house.
I detect a little bit of discord among some of the posts today perhaps this thread needs a little bit of that warm fuzzy feeling (Courtesy of Clubman)injected into it.