The 'chats' may be more meaningful than you realise - they may include monitoring of his mood and level of risk, helping him open up about his feelings, look at triggers, develop coping strategies, find ways to deal with stress or difficult feelings etc etc....all things that eventually build emotional resilience, reduce risk and lead to a 'cure'. Problems often take time to come about, and accordingly take time to be addressed.
I understand that for you as a parent you just want your son to stop feeling like this and for it all to go away, of course you do, but unfortunately it's never as simple as that.
However, it sounds like it would be good for you to speak to someone in CAMHS yourself for support about how to cope and to manage it all. CAMHS should be able to help with that.
This is the important bit though - if your son is actively suicidal then speak to someone in CAMHS urgently about your concerns. They may have a duty worker available tomorrow. If you don't feel that you can keep your son safe at home then you must discuss this with them and as suggested above, maybe inpatient care needs to be considered.
if you feel that your son is likely to make a serious attempt on his life then take him straight to A&E, tonight if you need to
I'm a CAMHS clinician, by the way.
Best wishes with all of it. I do understand how worrying and stressful this must be for you..