This is great advice. I'm also 26 and have come to the same basic realization (although only have worked one mundane IT job these past 3 years). The key is to develop a stoic mindset that can adapt to any phase of life you're in. Enjoying the present, doing your best, etc. Remind yourself when you forget. One thing I like to do is to imagine my current surroundings are in a foreign country, and for some reason it makes things more interesting and less mundane.

But I do think that some of this depression can come from not "letting it rip" and going after some goals. The fear of time passing you by and you never took a shot. So for me, I want to go do a slower type of travel where I can get fluent in a language or two. And sometimes, the thought that I'm not doing that and sitting in a desk job that is boring during my best years, makes me depressed.

The biggest task is: how do you link up the things you'd have the courage to "take the shot" for with things that can sustain you and your eventual future family? Still trying to figure that one out.