How do you know when a relationship isn't working?

Apparently it isn't when your boyfriend packs everything you have at his place into a suitcase and two laundry baskets and throws it out of his house into the rain.
I guess its not when you've cried so hard the night before Valentine's day that you burst multiple blood vessels in your eyes.
But when you, granted, in a fit of blacked out drunkenness, get into an argument about God knows what stupid bullshit, and it leads to you swallow 15 little white pills of Ambien....with the sick, twisted theory that maybe if you try to kill yourself he'll be nice to you for a little while....you get clued in.
And once you regain consciousness roughly 36 hours later and you realize what your little stunt put your friends and said boyfriend through (not to mention being incredibly lucky you did not, in fact, die) - the shame sets in. The utter shame, self loathing, personal disappointment that you, a beautiful, successful, 31 year old woman could do something so pathetic and so fucking stupid - is almost more that you can take. Let alone the fact that the man who was taking you ring shopping the week before is seriously reconsidering some major factors in his potential choice of future wife. Namely: sanity and stability.
And you are reconsidering...everything.
Neck deep in the shame spiral, trying not to mentally ass-rape myself, knowing that because I made a bad choice, doesn't mean I am a bad person, doesn't mean (necessarily) that i've undone everything healthy I gained in therapy (although Dr. B did get a call and I have an appointment on Friday), it doesn't mean I'm a mentally ill nutcase incapable of having a long term, meaningful relationship. Does it?
And the scary thing is that I know that none of these are the questions I should be asking. That I SHOULD be asking "why did I do it in the first place"? And the answer is...because...the thought of living without him is....not an appealing one.
That sentence is filled with all sorts of wrong. I know this. The only thing is that the idea of living in a war zone doesn't exactly leave me with warm and fuzzy, furry bunny feelings either.
The truth is that I want to stay. I want us to work. I want to be a sane, calm, normal girl that he can love. Not this crazy, codependent, clingy, pathetic shell of a woman I used to be. Frankly, I'd like to see that girl in the mirror again. I don't know when she disappeared. What's even scarier is that I don't know what to do to get her back.