Depression is when you cry but you don't know why you're crying. Depression is feeling like everything is going well only one minute of the day, and the rest of the day makes you feel like dying. Depression is weakness in your body from forgetting to eat. Depression is loud music to drown out your thoughts. Depression is fear of not being able to get up in the morning. Depression is fear of actually waking up and knowing you have to go on. Depression is fear of losing everyone and everything you love. Depression is breaking down whenever you are alone with your thoughts because you try your best to not let anyone see the darkness that you've got inside of you because for all you know it could be contagious and you wouldn't wish it upon your worst enemy.
I'm not diagnosed with depression but I think it's clear what I'm dealing with.