Hello Bipolartist: From what you wrote, it sounds to me as though what you're experiencing isn't that much different from what most people experience... perhaps somewhat more extreme. The fear of the unknown is deeply rooted. I certainly have it even though, for the most part, I know it is unfounded.

Mindfulness meditation is certainly a good practice to employ with this regard. The teachings of the Buddhist nun Pema Chödrön are particularly apropos. One of her books is even appropriately titled: Comfortable With Uncertainty. One must learn to "hold one's seat" (maintain equanimity) in the face of uncertainty. This is, however, not a skill that comes naturally to most people. And it can take a long time & allot of work to develop. But, as Pema teaches, we don't concern ourselves with how long it takes. We just do the work day-after-day. If it takes forever, it takes forever. My best wishes to you...