Welcome! Dear one, alas, if your friend insists on smoking weed, then I don't think there's much you can do, unless she is underage and then she could be reported to her parents or other authorities.

I know some people think weed is harmless, but it can have bad effects.

I also know you won't want to do this, but since your friend's behavior is upsetting you so much, then I suggest you tell her point blank that you are seeing bad results from her smoking and you will just have to stay away from her as long as she persists.

Please, if you are serious about wanting to kill yourself, then call a helpline. It would be helpful, too, to talk to a therapist about it. You might need some meds to help get you out of this depression. Take care of yourself. Okay?