Same thing happens to me time and again. I get passionate about X - spend all my time learning everything I can about X and one day I wake up and couldn't care

Same thing happens to me time and again. I get passionate about X - spend all my time learning everything I can about X and one day I wake up and couldn't care less about X. This happens once every 5 years. It's just the way I am and have made peace with it. The answer is to look for the next X that gets you passionate again - i.e. Y. This can be anything you choose - a new startup, get into software marketing, write a book, teach .... the world is your oyster.