Welcome and thank you for reaching our forums.
Having colleagues who don't understand your situation can be extremely difficult to deal with. I understand why you dread going back.
I'm guessing your supervisor and HR are aware of your condition, since you've taken time off work. Are they understanding? If yes, is it possible for them to step in and explain your situation to your colleagues?
If you feel like this workplace isn't the place where you will get the right kind of support, then leaving would be a good option. However, please do think about whether you're ready to look for another job, because that too can be a very stressful exercise.