I have learned in life that there is good and bad to doubt.
Good that so often it makes us stop and look at things from all angles before we make the decision. Bad as what you have shown through your two stories. It can either "eat us up" from the inside with time or it can make us act wrongly.

In the end, we can all admit that doubt is a pretty natural part of life and we have to learn to embrace it in the right manner.

Best wishes!