One in five young people has a very clear sense of purpose, according to psychologist bill damon. You can't just throw yourself into some good work only because it's obviously of moral consequence - you have to enjoy doing it. I would think that an existential thought, even existential dread, is a really useful signal. If you can solve any problem in te universe and make a positive difference, then you'll likely be a happy and fulfilled person.
Also: what is the meaning of life?