You are experiencing what we all feel at times. I suggest you remember to take good care of yourself too! The mental health crisis hotlines are for people like us too. We need our own mental health support with meds and counseling. I did both.
I also put him in an assisted living home with med support and I had constant contact with the administrator and the doctor until his meds were made right. It gave me the space to heal some and get some much needed sleep. My son had gotten to the point he was in as much pain (as I was too) and we made a deal to "do whatever it takes". That was on both of our points. That was 3 1/2 year ago.
He has graduated to living with his sister and is stable!!! I am sane and he is so much happier. He still needs to start college and/or working to be back into society and being productive.
I hope you find the right combo of things to get you both where you need to be. Keep trying!
Our job as a parents (usually without spousal support and sometimes without friend support) is a very difficult and hard palace to be. There is no shame in getting the help you need for you and for your son.
Hang in there, keep trying and reach out for help. That is what we are here for.