If you're that close you need to get into a hospital. No one wants to hear that suggestion, but now is the time before it's too late. I've been there. I didn't go into hospital and I very nearly ended it in a sure fire way. Your friend would be devastated. You clearly mean something to him. Let him help. Help yourself by letting him help. He has good instincts about how to do it. Let him in. The world would minus a good person without you.