I work in a small hospital in a smaller town. I was "formed" a couple of years ago in our emergency room and sent to another hospital with a mental health unit. Nothing like a public breakdown!

I was off for a few months and was terrified of going back to work and facing people. A few people knew what had happened but many didn't. I was afraid of the questions. One of the allied health workers at the hospital gave me the simplest response. Q: "Where have you been? What's up? etc..." A:"I was off sick. I'm back now" That simple, he told me that no one needs to know, it's none of their business. A simple answer often shuts down more questions.
I wish you strength on your return to work.