Bucket paint working terribly slow

So i was doing an animation and finally got to painting. For some unknown reason everytime i use the bucket tool, the program takes like minutes to paint the thing. I have to sit there waiting for it to fill. I just clicked on the small gap and it still takes so long to fill it, like why. Then when it finally loads, i accidentally click on something with the bucket tool on. And it will take an eternity to load again. Something that i noticed is that in other smaller frames this doesnt happen. But frames with big gaps and space, it happens.

Can somebody please tell whats going on, it really takes all of my time away just to color spaces. Is it my computer?