Meditation is free, so is walking. Journaling is another option. You could also spend time watching funny/happy/cute videos at the library. You could also talk to your friends, just spend a night in with friends can help.

Why do you feel excluded at your job? Parhaps you just need to find common ground outside work to talk about. If you work in a cubicle, put up stuff that makes you happy. [Pictures of loved ones, pictures that make you smile, your artwork, funny/inspiring quotes]