Shapes, brushes drawn ,created wont`t be seen

Hi, I have encountered a problem in photoshop. any shape i wanna draw, even with pentool, or bucket tool, brushes, it won`t be seen anymore. it actually happened while i was working, the shape right in the left can be seen, but after that I managed to be in a hurry and while I was typing quickly, the working mode changed to full screen. I`ve read some posts about reseting the general settings but didn`t help. can anyone please, help me? thanks a lot!
