An after the fact reply for info....congratulations on finding your way out of the dilemma.
If you hover your cursor over the little Green dot in the upper left corner of the Excel window, you should get a tool-tip contextual info that will tell you about entering Full Screen mode....and OBTW, to exit Full Screen mode simply hit the Escape key. To show the header portion of the Window (which seemingly goes away while in Full Screen mode), simply run your cursor up to the top limit of your screen and the header will pop down into view....this would also allow you to exit Full Screen mode by toggling the little Green dot a second time.
