Low effort job, but very high stress to the point of a breakdown. What do I do now?

I recently had a mental breakdown and applied for mental health leave from my job. It’s a very low effort job, but it is extremely high stress and has left me broken. I used to love my job, but I don’t anymore. I feel like I don’t really know who I am or what I want anymore. I’m 41 years old, and I don’t really want to spend my next 25 years being miserable, but I don’t really know what else I can do and this is my only career for the past 15 years. I’m feeling incredibly overwhelmed and undervalued. I am expecting to go back to this job in six months, but I’m thinking about leaving, and I don’t know how to make a change at this point.