If you're not sure about something. You're probably experiencing a degree of uncertainty. It is impossible to do more than guess at the result or the outcome.
Doubt in other hand, implies both uncertainty and inability to make a decision because the evidence is insufficient.
Different to Dubiety, dubiety comes closer in meaning to uncertainty than to doubt, because it stresses a lack of sureness than an inability to reach a destination but unlike uncertainty, it connotes wavering or fluctuating between one conclusion and another.
In life, uncertainty is common.
We all have something that we are not sure of.