Was Tolkien Depressed?

[Elendur]

The answer to your question was answered by Tolkien already.

Now it is a strange thing, but things that are good to have and days that are good to spend are soon told about, and not much to listen to; while things that are uncomfortable, palpitating, and even gruesome, may make a good tale, and take a deal of telling anyway.

- A Short Rest, The Hobbit

Maybe you would be interested to read about Melkor dancing along the shoreline with Ulmo and having a freindly arm wrestling match with Tulkas, but most people wouldn't. I think you understand what Im saying...

Hope this helped.