Lost my sims 3 tab after pressing command+return.

Playing sims 3 on mac. Pressed return +  command to go back to desktop without quitting game but instead the sims 3 tab is now missing! I know the tab is still open somewhere because I can hear the game's music, but whenever I press the sims 3 application, no window opens or shows. I cannot enter origin as it gives me a message saying somebody else is using it and has to quit the application. I've tried bringing all windows to front and pressing f3 but nothing has worked