Why does my arrow tool change to a cross

I have been spending the ENTIRE day trying to get this cross to go away. Here is the problem: I have made a mask on a layer and for no good reason I can think of, the pointer tool is now in the shape of a small cross. If I click it it hides everything and makes an unwanted white square but still maintains the cross or it looks like I can make a plethera of white squares. Why Iwould want that I don't know. I shut down the program without saving it in the hopes I would then open it up to a a regular arrow tool, but no luck with that. I stull have the stupid cross. Help!