[remarkEon]

A couple other comments alluded to this, but the advice I would give (as someone who felt lost when I was way younger and joined the Army to fix it) is to get in great shape. Doesn't have to be some crazy fitness goal, maybe something simple like "I want to be able to do 80 pushups without stopping".

For your health, obviously, this is good. But it's also a gateway to meeting new friends. Your weight lifting buddy suddenly invites you out to grab a beer or go to a ballgame, and suddenly his/her friends are your friends and then that longing for Monday starts to dissipate a bit. It can be a real gateway.