Let's get serious here. Having depression doesn't mean that a person is weak, or a failure, or isn't really trying.
Depression is a very real and common illness.
Sometimes, like other ilnnesses, depression just happens. Other times, depression can follow something like a divorce or death in the family, someone you love getting busted, a move, or a messed up home life. So remember, when your problems seem too big, and you're feeling too low for too long, you're not alone. There's help out there. You really can ask for help.