Well, dictionary defines uncertainty as 'the state of being unsure of something,' but in the real sense uncertainty plays an active role in initiating depression as it finds it way into our emotions and feelings.
Uncertainty is aversive and associated with negative emotional states such as fear and anxiety.
Life is often fraught with uncertainty, as we cannot predict the future, constructing a framework to draw from, helps us in having a grounded idea of what our next steps might look like. But uncertainty try to mess up whole construction, giving out doubts and make us not so sure of whether we're doing it right. This particular feeling kill ideas.
Dealing with uncertainty, you have to;
If you're out there struggling with uncertainty, all you need is 'trust in yourself', uncertainty is a feeling and there's no medication for it. A piece of self esteem and a reliable source of information is enough to engulf it.