Could barely-two-months-old Union Square Donuts be expanding already? The tiny Somerville shop has been delighting and agonizing fans with its limited hours and inventory since opening, but changes are apparently brewing. "We are in the midst of making some wonderful changes, which will mean more donuts and more space," wrote the bakery on Facebook yesterday. "With that said we unfortunately will be closed tomorrow and over the weekend. Our hopes are to be back making donuts VERY SOON. Many yummy new donuts flavors will be coming out soon!!" Are they taking over an adjacent space? Adding a new location? Hiring a small army of expert donut-makers? In any case, the mystery changes will hopefully put a stop to the pangs of disappointment felt by the local donut-loving community every time Union Square Donuts sells out after just a few hours of business.