I know when I used FMLA, my principal and superintendent knew the reasons. Even though I didn't technially access the FMLA for PTSD-related time off (because it wasn't consecutive or in access of a certain number of days), the same people knew. No one but me got to decide to tell my co-workers. I told my husband and I carefully explained why I needed to take days off (because I couldn't get alone time to think or relax otherwise) and he was very understanding. I arranged to take 1 day off per week for about 7 weeks and it was extremely helpful. It was perfect for me. I wished I could have done it for longer (which I suppose, technically I could, but that is a long story). Good luck with your decision-making about taking time off.