Flirting with happiness

I want to be happy and flirt with happiness, yet find it takes very little to tip me into despair and wish I knew how to prevent that from happening. My recovery time is getting shorter when this happens though and I know there is a learning lesson in it, but what exactly that lesson is, seems to be elusive.
I push people away who get too close and find the ones I know that I could probably lean on, I won't allow to see me at my most vulnerable for fear of abandonment. Most people do not know what to do with another person's vulnerability. Some want to jump in and fix what they perceive to be broken and others seem to see it as something that they will catch so they run for the hills. It is the rare find that will allow one to cry, vent or to bury themselves in the warmth and caring of their comforting embrace, wordlessly supporting, yet not enabling the despondent to sink into their despair, without judgement and giving advice only when asked.
In spite of my angst I do see myself as a happy person, or perhaps, more accurately as one who is content with settling for close enough. Euphoria is not something that can be sustained for long periods and there is no place to go but down from such heights.
So for now I will choose the halfway point and desire be content with that, while allowing room for the highs and lows to colour my life.