I was probably depressed in middle school, but I learned I had seasonal depression in college, thanks to higher stress and a poorly lit dorm room. I just remember feeling like I was in one of those SF movies where all the people have disappeared but it looks like they just stepped out to go get milk from the store. I literally had to surround myself with happy people (even the voices on the radio*) to not feel overwhelmingly lonely and as soon as I wasn't focusing on being with people, I crashed.

The meds basically tended to act like a pothole filler. I still felt sad or anxious sometimes, but I was less likely to be so deep I couldn't work myself out.

* And my stupid brain wouldn't take iTunes because we knew it was recorded. They had to be real people.