My only advice is: if you burn out, go through the entire process. You only get one chance to figure out what actually is meaningful to you, and the answer will most likely require you to upend you life (or you wouldn't have burned out in the first place). Read Carl Jung: he did a lot of research on midlife crises, and the enormous significance of middle age (the 30-40 years old range) in our quest for meaning.
In my very personal case, meaning was figuring out I'm meant to build things, on my own, at my own pace, and I owe the world to gift it with the vision that only I possess. Meaning for me happens to be one part about becoming a fully creative person, and one part about being selfless with my work, for I am not entitled to the result (see karma yoga). Your mileage might certainly vary.
Feel free to send me an email if you want to talk more about it.
All this to say, a person trained to work for someone else 40 hours a week for all their adult life is not able to self-direct and find meaning without a lot of introspection and readjusting.