How do I repair my reputation at work and enjoy life there again?

Desist and Refrain from saying anything ood or bad about co-workers. Be friendly to everyone even if they are nasty to you and by friendly i do not mean all up in their face but you need to keep your cool and do not let them see it has affected you. If possible, pull your co-workers aside without mentioning any name and say you know i was giving a joke about you the other day...and play if off like that. Try to focus more on your job.