If in your thoughts you think "is there any particular reason I should be unhappy?", maybe as you 'think' you are becoming depressed about things, consider that you're basically challenging yourself to find something. And yes, you will. You are good at it, after all.

Maybe don't try to quantify the amount of unhappy. It's there, oh wells. Right now you are physically safe which is what your brain is really asking yourself; for self-preservation purposes.

Your idle thread is your worry thread. The more you hand out to yourself the more you'll hate yourself for not being out there hunting for your wife and kids (you're a caveman, see?)