Nope, depression comes in many shapes and forms, and "going down the rabbit hole" is usually the easier path to take for severely depressed individuals.

The effort you are implying here – the "escalation" to get motivated and try to accomplish things is both environmental and inherent, and sometimes genetics factors in as well. Some people are born predisposed to clinical depression, even, regardless on how "well" an environment, economically or otherwise, they were born in.

Not saying it's not possible to just do these things, but depression, especially the clinical type, doesn't exactly "go away" with a pat in the head and a good luck charm. It takes therapy, dedication and patience to get rid of those annoying, negative thoughts. Abnormal, recurrent tiredness could very well be a symptom of a worsening depressive state.