I never returned to the certainty I once had. My "views on spirituality or philosophy" have gone through approx. four major changes and many minor ones.
Major doubts can be looked at as a kind of metamorphosis. Each time, you arrive at a bigger picture or viewpoint. The bigger the picture, the less likely that a clash with another view or some underlying incongruity will poke holes in it. So the question is, what is the biggest picture possible? Or perhaps, what is the biggest picture that seems right at the present time?
I hope this helps, Lark, or that you find other help in this thread if you're experiencing doubts. Doubts can be difficult to work through, because the process can involve leaving intellectual safety, emotional familiarity, or even family or social groups (or being ousted by them).