Stopping suicide

I has this guy start talking to me and when I declined his offer to go out with him. He started telling me that he was going to kill himself and everything. I don't know how to deal with the situation because I think he was trying to make me feel bad for declining his offer. He also go really mad at me for not responding and he is just really controlling even though he just started talking to me yesterday. Does anyone have any advice?????✨✨✨✨