Teen emotional abuse

I've been with this guy for almost a year now, but for a while I really haven't been feeling it due to incompatibility and lack of time for eachother. I was upset last night and I finally tried to make it clear that I only wanted to be friends. I understand it could be hard for him, so I was very kind about it and explained myself the best I could. Then before I knew it he texted me and told me he drank a bottle of NyQuil and that he was getting in his car to drive. I stayed up all night panicking and begging him not to drive and to get help. Sure enough this morning I tried to reach him again and he told me he was fine.  This isn't the first time he has threatened suicide because I don't want to be with him. I'm a loss of what to do and so under pressure, please help.