I was an emotional wreck from age 44-49 because my professional life was stagnant. My 50th birthday went unnoticed, but I no longer cared.
I learned that life isn't your job, but it's how you respond to each moment. I'm still in a job that doesn't satisfy me, but I found other things to fulfill me.
I'm much happier "over the hill" because I no longer set my expectations based on what society or other people expect.