Five years ago, I started the habit of turning off my phone at 8pm so I would not get distress calls in the middle of the night. A number of times, my son had called me in a panic about the police being at his apartment or other such things. My therapist said that as a result I was suffering my own PTSD.
I believe it. You've had a hell of a ride. And now is the time when you've got to take care of you. Doesn't mean you don't care about him. Doesn't mean you won't worry about him. Because you will.
Of course you will.
What it does mean is while he's your son and you'll always love him, you have to protect yourself and allow yourself to heal. That comes first.