I was in bed too, it started off as a bit of pop and a trickle, then I had maybe a minute before it started to gush (so it would've been highly embarrassing had I been at the supermarket!)
It is unfortunate when the waters break first, cos like others found, the contractions started but labour didn't kick in properly, and hence I needed IV antibiotics and induction etc etc, where as if my waters hadn't broken, things might have progressed ok naturally.
It's definitely not a case of normal = waters break, baby pops out an hour or two later

(how little TV/movies prepare you for real life!)