Depression is more than feeling 'a little sad sometimes'.
Being sad is normal. It's a human emotion and we've all experienced being sad. Sadness comes and goes. When you're sad you feel bad and you might cry, but sooner or later this feeling goes away. It always goes away.
Depression isn't like that. Depression is an emotional state, a mental illness that affects our thinking, our emotions, our perceptions. You think differently, you behave differently. You feel horrible, most of the time you don't even know why. You just feel like you don't belong, like you don't fit in in this world.

Depression isn't 'feeling down'. It's not. It's like a darkness that creeps over you and fills you. It drains all you emotions. It takes everything from you and leaves you feeling hollow and numb. It's not sadness, it's not anger, it's hopelessness and fear. It's a numb, empty feeling that seems to never leave.
It's feeling alone in a room full of people. It's feeling like there's no hope left.

Sometimes you don't even feel at all. You don't care about anything or anyone, esspecially not yourself. You don't take care of yourself anymore. You just lie in bed trying to get rid of the constant tiredness but you can't find sleep.

You seek for a way out, a way to feel better, a way to actually feel something at all. You start smoking and drinking. You want to feel anything at all so you smoke a cigarette, light up a joint or take another pill. You get addicted. You get addicted to the things that help you want to live for a little longer. That's the thing about drugs, it makes you feel a little happier for a little while, but it always ends. Always.
So you take another pill to make you forget and you know it's bad for you but you just don't care. You just want to feel. You just want to be less anxious, less alone.

Depression is feeling worthless, hopeless, scared. You hate yourself and the way you look. Mirrors are your worst enemies. You just feel this overwhelming self-loathing pain inside.
You start hurting yourself because you blame yourself. You cut because it moves the pain from inside to a wound.
You start isolating yourself from your family because you just feel incredibly guilty. You feel like you let down everyone. You feel guilty because you can't be the daughter or sister your family wants and needs you to be.

No, depression isn't feeling sad. It's about losing everything, even yourself.
It's about destroying yourself because life is just an hourglass to you and you can't wait for it to run out of sand.