My college roommate was a physics major, and she explained to me one night how the theory of relativity applies to everything. I must have been feeling pretty lucid, because I remember this as an a-ha moment. Probably we were drinking beer in the bar with our names on the wall. Here's what she said: As you get older, time goes faster, because each day takes up a smaller fraction of your life.
This is why when you're 3 years old, waiting until the end of December for Santa to show up takes FOREVER. This is why when you're 43 years old, you blink and another month is already over. Hopefully when you're 83 years old, you'll be drinking white wine spritzers on the beach and won't care what month it is.
So I blinked and now it's February, and what happened to January? Computer goblins happened to January. They ate four chapters. I'd backed up the first 7. I have no explanation for why I stopped backing up after chapter 7. It's been a little bit of a momentum killer for me, even though I knew I was going to rewrite the whole thing anyway (3rd person vs 1st person, anyone?). I take some consolation knowing I'm not the first writer who's experienced this. I just need to pick up and get going again where the story in its current state leaves off. Writing is all about persistence and not giving up, anyway.
Truly, time flies. And it's flying faster every day. Persistently using the time you have will naturally create momentum. Pesky goblins be damned!