I'm sorry you have to go through this. I have been having a rough time with my son lately although not as rough as poor you. You said your son is bigger than you - how old is he?
I understand the feelings of intense frustration and I am sure, despair.
I really hope today is easier on you.
If you have no deadline to meet as far as the text books are concerned, put them on the bookshelf for a while. Just until you have caught your breath again.
Take care!