Color Tool Error

My color tool on Illustrator appears as pictured below: pixelated and with limited colors. I would just use hex codes to color my artwork, but when I open the color tool for a shape I already have the color I want it changes the color to one of the ones on this pixelated gradient. For example, the color element from this screenshot was originally the brown color on the right but turns to the olive green color when I open the color options. I've tried restarting the app with no success. Does anyone know how to fix this problem?