I think the crushing-ness may come from a (somewhat justifiable, IMHO) fear of solipsism. "Because I want to" is a fundamentally ego-centric view of the universe: your feelings are your own, so what happens if nobody else wants what I want? Are we then alone in the universe?

The solution (at least for me) comes from expanding our view of what "I want" to include people close to us and the outside world as well. And so I do what I want, but my wants also include making the people I care about happy, being a net positive influence on the world, and not turning away from reality even when it seems bleak or painful. In this way, there's no contradiction between achieving things and doing what I want to be doing.

"Be good to yourself, and to others. You cannot do one or the other; it has to be both, or neither."