This is a game.
As a player who plays for the sake of playing, I quit when I want to, and come back when I want to.
If you are a mapper though, you are creating (game) content, for free, the noblest form of art. This of course comes with all the implications and that is where "community" comes in. You would become invested and attached and this is where it becomes psychologically similar to drastical changes in life like quitting a career. The same applies when you play competitively (however silly that sounds) where the talents, effort, interest and all that jazz you slap on every aspect of life get argued about.
Deal with it. Don't hesitate to seek help (talk to a confidant or if serious enough, professionals etc) in dealing with it.
Like many things, gaming might be a huge part of our lives but ultimately it's as big as what we make it to be.