Well, first off, its always hard for a mother to know that their child is hurting or having troubles.
I broke my mother's heart many years ago myself, but we now have a relatively decent relationship. When she finally understood the amount of pain I was in, it made it easier for her to know and relate to what I was going through, although it was definitely hard for her. But because of that, she helped me get the help I needed. When I started getting a handle on things, and really utilized the tools out there to get to a place where I could better handle my issues and live a decent life, she felt better as well. I think that reaching out by writing was a good start, even though its rough. Talk to her, let her know what's going on, talk to her about how you're seeking treatment, and I'm sure she'll feel good that you're willing to share your thoughts and feelings with her. Remember that you don't have to make the journey alone.
PTSD is a very difficult monster to face, as well as schizophrenia (I only have experience with PTSD, though). But once you really get a good handle on those things, life will get better.. Its sounds like you've made a good start.