Everyone has given some good advice, and I certainly understand the angst you feel while you stand by helplessly and watch your son slide that long slide of depression. From what you have told us, it sounds to me that he might have schizo-affective disorder, but not being a therapist or a psychologist, I have no way of knowing for sure. I just tend to listen and hear what you have been saying about his ways.
Being a single mom is such a strain on us at times, especially when we see our children make mistakes that cost dearly. It sounds like he is very appropriate with you, and respects you. That is a great start for him. I understand that you want to do anything and everything you can for him, and I understand the pain it puts you in.
If you don't have a therapist or psychologist, you can usually dial 211 and ask them to point you in a therapist's direction. The 211 is United Way, and they have all sorts of resources available for you. I would print off the first explanation you gave for him giving you concern, and then I would point blank ask the therapist if he/she would be willing to see him. If he has no insurance, then he would be transferred to the County Mental Health system, given a therapist, and they would start working with him right away. they can even suggest to you about how you should be with him--whether tough love is an option--even though it doesn't sound like he could handle tough love right now and he might feel like you are on the attack with him. Giving him some options, and making sure he follows through with them would help give you some peace of mind about his outcome. If they feel it necessary, they might suggest that he move into a group home until he is more stable and monitored. There are many options for both of you, you just have to keep at it until you find the right combination of things to help him--but first and foremost, see a therapist yourself so that you know where you are before you help him. It is much easier to acquiesce to him than to steer him in the right direction with the help of a therapist. And could be that he doesn't open up much to you because he is ashamed for how he is right now. But the fact that he is respectful to you makes me think he might listen to you about going to see a therapist, if only for your sake.
My prayers are with you. Know that it is not easy seeing your child in such pain--emotionally and psychologically. Protect your own self first, because then you will be better prepared to handle whatever may come your way.
Jewels

