The kundalini flows upward. It also flows downward in different ways. It is quite complex, actually.
Bodies come and go, ages come and go, yugas come and go, eternities come and go. Selves come and go.
Self-realization is not the awareness that this world is a dream, that's a part of self-realization.
There is no such thing as spiritual achievement; it is simply an awareness intrinsic to all of life.