I've been editing designs for a logo, cleaning up lines and colors for the last few days working 5+ hours a day. Been using mostly the paint brush and easer brush. Today on one layer (the same one I was working on yesterday) both brushes are not working correctly. They are both set at 100% opacity, flow, and hardness but with the paint brush it isn't painting a solid color. It's pixelated, and skips space and will not "color in" a line to make it darker. The eraser is doing the same thing. It will not erase fully. I added a pixel layer and both brushes work fine, exactly like they should, but on the layer I need they will not. I've attached a screenshot of the full page, the little lines that the arrows are point at are the examples. I am usually zoomed in very close and working 1-5 pixels at a time for this which I also included a screenshot of. I don't know what has happened to this one layer after closing the program last night and opening it today.
I still have a lot of work to get done on this and I can't do anything if this isn't working. What caused this? How can I fix it?