[smk_]

Happiness always reverts back to a baseline level. You will never escape this baseline level.

Up until this point in your life, meaning has been a projection – a goal ahead of you. You have now reached this goal, realised the projection, and must find a new projection, a new project. You must find an I beyond the self, a goal that encompasses but is larger than yourself.

I recommend the book "What is Existentialism?" by Simone de Beauvoir as a starting point.