mind? what mind?

Whip up the waves of non-being and wash me away!
How long will I walk up and down the shore in fear?
- Jalal-ud-Din Rumi
(Translated by Andrew Harvey from A Year of Rumi)

Non-being.  A core understanding and belief of the Buddhist philosophy (and others?),  Does that mean non-existence?  Existence without form?  I’ve read in texts that it is both, and neither.  How’s that for definitive?  At a gut level, I am not certain how I feel about not “being”.  As a life-long sufferer of severe depression and other ailments, non-being has had it’s attractiveness for certain.  But as a somewhat-practicing-follower-of-Buddhist-thought, the steps that need to be taken to “get there” will take someone like me many, many… no, uncountable eons of lifetimes to achieve this state, and that, my friends, is scary.  Which is why I, like Rumi, wonder “how long will I walk up and down the shore [of non-being] in fear”?