You don't obtain foundations... you already have them. It sounds to me like you just need to identify yours.

rainbowloom puts it as well as I could have said it. I have often felt the way you described, sadlife, especially through much of my adolescence. As far as things that I can count on, anything reliable, anything stable -- even now I don't always feel like I have much.

It's definitely been a process to learn to identify the small things within myself that I can count on, or the tools that I can use to remind myself of those things. One of the more recent things I've found useful is when I feel like I'm totally overwhelmed and everything around me is complete chaos and I don't have any control over anything...

Is to begin singing (to myself silently if I'm in public, or out loud when I can) the chorus of The Beatles' "Across The Universe":

Nothing's gonna change my world.
Nothing's gonna change my world.
Nothing's gonna change my world.
Nothing's gonna change my world.

Yeah, maybe it's silly. Maybe it's trite. But it works for me, gives me -- even if only for a brief moment -- something to hold onto, to stand on. A foundation. And I think that practicing finding those momentary foundations accumulates toward finding longer-lasting foundations, and stronger ones, or at least finding the small ones more quickly and easily.

The folks who have their own strong foundations, clearly marked and functional... likely also had help in laying those foundations early and well. Those of us who didn't start with great stability, or who didn't have great examples of how to identify and use those foundations, end up with lots more learning to do in a much shorter time period. And it does take time, like learning any skill, as well as practice. But it is possible!