It sounds like you were fortunate to have your passion and career be one and the same for 2 decades. Many people do not have this blessing, so ask yourself: what does everyone else do in this case? Personally, I think trying to find purpose/meaning/happiness in your life is the point of life.

This is to say, you'll probably need to hunt for hobbies and find something that gives you meaning, now that the IT-shine is gone.