We learn to trust when we are babies (and I think that it even continues beyond that). From what you have told me about the mother, she only gave you reasons to distrust her. This stuff, while growing up, gets embedded pretty deep. Your reflex is to not trust anyone. You can change it with work and focus. (But only trusting those who have earned it).

I have heard many times that the best time to go to therapy is when you don't want to go.