Hello @Single-mum, sorry to hear that things have been tough for you lately. It sounds like you have been supportive of your son and that you have been active in getting him the help that he has been needing. The incident that you spoke of sounded very difficult. It must have been hard for you to see your son in that state. Have you been able to discuss your son's behaviour with a support person from the school? It might be helpful for you talk with the school counsellor or psychologist as they might be able to support you and your son and provide you with some appropriate referrals.
It sounds like things have been tough for you lately, so I am wondering if you have been able to talk to anyone about what you have been through and the impacts it has had on you? Parentline is a free and confidential service for parents and carers which you can call to talk to a trained counsellor. You can talk through your concerns with them and they can help support you. SMART Recovery is another service that you might find to be useful. They offer support to family and friends of those who use drugs and alcohol, and hope to help develop more effective coping strategies.
We also have an article about managing teenagers and their drug use, that you might find to be helpful. Here is a link to the article if you are interested. I hope that you find these resources to be helpful 
