Hello, I’d like to wish happy holidays to all of you and ask one question.

I will hopefully be invited to a New Year party with a couple of my friends and their spouses. But I have a little problem: I’m taking anti-psychotics and sleep pills, so alcohol is out of question. My friends, unfortunately, haven’t discovered yet that you can have fun without being dead drunk, so they’ll ask me questions. Should I tell them truth? Of course, I won’t tell them everything, just that I“ had some physical symptoms no doctor could diagnose till I was sent to a psychotherapist. Now I take an unspecified medicine and sleep pills to treat the side effects.” It's not a lie, but a bare minimum so they won’t consider me crazy or pity me.
My mom warned me against this, but I don't want to lie anymore. A part of me itches to tell everybody just to see their reaction. I'm terrible at keeping secrets