i believe that you're thinking of confirmation bias, which is more like holding a belief despite being challenged with logical evidence.

cognitive dissonance is more like holding two ideas simultaneously which seem to conflict with one another. the cognitive load (how much you have to think about something) is high because you are trying to square these two competing thoughts/ideas.

a quick and simple example of cognitive dissonance is knowing that smoking is bad for your health, but continuing to do so, using the excuse that you have high stress and the nicotine mitigates that stress.

just to contrast, confirmation bias in the same example would be someone telling you that smoking is bad for you (citing legitimate evidence), but you continue to believe that it's fine to smoke because you like to smoke.

hope this helps to distinguish the two

I think it actually refers to the uncomfortable feeling that comes with contradictory information. It is a reason people don’t want to accept certain ideas even when presented with evidence that support it.