Claustrophobia. I agree w dr. Hazlet, the other options is taking cognitive behavior therapy or finding a bigger office.
Simple things first. Get rid of clutter or unnecessary things in your space. Plain and simple is best. Place a good sized mirror in your space if possible to reflect more light in and it will make your space seem larger and less claustrophobic. If you don't need the big desks or tables, downsize them. Can you trade to get a new space? You might talk to your boss. If that fails you may need a new job. You can do it.