What loka said. I was depressed, and still have my depressive cycles.

The trick is not to think about it. Occupy your mind with things. Programming, gaming, reading, working out, etc etc etc. Keep a positive outlook. Remember, be thankful for what you have and what God has given you... and be thankful you're American and are able to enlist in the USMC -- it's not that easy for some of us.

And yes, even though alcohol is a depressant, it actually relieved some of my stresses.