Has anyone noticed you find yourself reading or watching TV or at laptop ... and your mouth has dropped open?

I have caught myself doing this a dozen times or more since I started Pristiq. Is this related to the jaw clenching side effect I've seen in so many posts? I hate it -- I work in an office with "open seating" and I'm afraid my coworkers think I've suddenly turned into a "feeb" or something :)

Seriously, it's weird and annoying ... any insights out there?