This must be so awful for you, Melissa..I can only imagine what you are going through.
My advice comes from an objective point a view, times I can be too direct. I know he is your son, but for now let them tend to his needs, evaluate him. Right now he is in a place where he is protected from himself and everyone is safe from him...as he seems so unpredictable.
You have to put yourself first...you and I have talked about being selfish. This isn't about eating the last morsel, this is your life....and if you continue at this pace...what life? So, call up you doctor, advise them about your back pain...losing eye sight. We can not diagnose you, prescribed anything here...so please call and make an appointment first thing tomorrow..or even go the ER tonight.
If you are not around, God forbid how will you be able to help your son...
Priorities, please rearrange...and out yourself at the top of the list. I know your heart hurts, but you have to do this, for yourself, for your son...please see a doctor.
I'll be logged on and will be here on and off....if you what to chat more.