While we're waiting for a more specific answer, I've written a little bit about this in the past:

How fast did the news of the conquest of Constantinople 1453 travel to western Europe? Was is any faster than when it was sacked in 1204?
How did Venice react to the fall of Constantinople and the end of the Byzantine Empire?

Basically everyone was sad and angry (at least in Venice, where we know the reaction of the crowd). The pope tried to organize a new crusade but there wasn't much enthusiasm for it, so apparently "shocked, but not willing to do anything about it" was the general response.