It happens. "Facebook depression" seems to be one of those things that has crept up in recent years. It used to be we would run into some old friend or acquaintance at the supermarket who gushes on and on about their life for five minutes. Then we leave, and never see them again. Now we see what that person is doing 24/7. Social networking is a narcissist's dream come true. It's also why they created filters, to block out the annoying people who post all the time.
Just remember: People who TMI all over Facebook are usually overcompensating for something. Nobody is that happy or that interesting. Chances are their real lives are pretty boring. Documenting your life 24/7 means you aren't living it. Real, quality experiences happen in the moments between iPhone camera snaps, tags, "likes" and status updates. If everything is special, then nothing is special. You're out there living life while everyone else is posting about it.
Good for you for getting away from Facebook if it was bringing you down. Of course, if you ever do go back to Facebook, you could spend some time over on the GuySpeak Facebook page. Plenty of nice, non-egotistical folks there.