How does someone know when they suffer from clinical depression? Is there a checklist where if you score 10/20, you must be depressed?

This question arose when I read Hugh Laurie saying that he realized he was suffering from depression because he felt nothing as drove around exploding cars in an event. It came back to me when I was watching a stripper gyrate her hips and realized I was more interested in a catfish cookbook.

So, I've been trying to find out if I have a hormone imbalance somewhere or if my brain is malfunctioning. Looking online, I find really, really useless information about depression where practically everything anyone can do can potentially be depression-related.

"Are you afraid of meeting people or find yourself relying too much on people?"

"Do you have a lack of appetite or find yourself eating too much?"

How on earth is that helpful? And how is someone who's depressed supposed to know they "experience bouts of helplessness more than usual"?

For myself, I've come to a conclusion that I'm probably not depressed. Most likely is that I'm just massively bored and for someone who takes a lot of pleasure in indulging in extremes, I'm starting to run out of extremes. By extremes, I don't mean jumping out of a plane or flipping a skateboard, I mean agreeing to kill for profit or fucking a cow.

Not that I've killed anyone or fucked a cow. So far as you know.