I'm co-dependent and I need someone

I'm co-dependent and I need someone... I'm falling apart after my relationship ended. I've been trying to do the things people say; go out and meet people, just get outside. Nothing helps. I break down in the grocery store. I don't want to leave the house anymore. I sit home and cry all day & think about jabbing a knife in my throat. I just want her back and to love and live again.