When I used to think of depression, I had a set image in my head. I thought it was puffy, red lines on creamy white wrists, I thought it was lines of black eyeliner painted on tear-streaked cheeks, I thought it was the physical inability to get up out of bed and achieve any form of productivity.
For that reason, I didn't feel like I deserved to give my feelings a name so severe as depression. Everyone feels sad sometimes, and I never thought I was an exception. As long as I was getting out of bed in the morning, there couldn't really be a problem. I had everything I could ever want at this point in my life. I was exactly where I wanted to be. Having a "down day" is normal.
But having them every day is not.
Depression isn't always melted eyeliner and uneven lines up your wrist. Sometimes depression means getting up out of bed just like you're supposed to, getting in the car just like you're supposed to so you can get to school or work and daydreaming about driving off the road. Sometimes it means clicking through songs on your phone until you get to the one you imagine playing at your funeral. Sometimes depression just means shutting down for a few days even with the people you care about most, and being fully aware of what you're doing and how it's unfair to them, but not being able to force yourself to care in conversations. Sometimes depression is focusing all your attention on what seems meaningless to other people because it's the only thing you find meaning in.
Sometimes depression has no reason. That doesn't mean it's not there, and it doesn't make someone's feelings any less valid.
Sometimes it just means riding out a wave and getting sucked under, trusting that you'll eventually land on the shore again.