Your feremntation didn't stop, all that happened is the need to VENT EXCESS CO2 VIA THE AIRLOCK RELEASE VALVE decreased. The airlock is NOT a Fermentation Gauge, it is a cheap piece of chinese plastic, used to keep the bucket from blowing, and should be viewed as nothing more.
If it's not bubbling that just means that there's not enough CO2 to climb out of the airlock, or the CO2 is just forming a nice cushion on top of the beer like it's supposed to, or the airlock is askew, or it is leaking out the cheap rubber grommet, or you have a leak in the bucket seal...all those are fine...if CO2 is getting out then nothing's getting in....
Over half of my beers have had no airlock activity...
Read this...
http://blogs.homebrewtalk.com/Revvy/Think_evaluation_before_action/
Relying on the airlock is one of those bad brewing practices I wish we could excise from all the brewing books...it may have been a good gauge back 20 or more years ago when (When Charlie P wrote the bible of brewing, and bleach was the main sanitizer) and the main airlock used was the infallible S type, and especially those made of glass that sat heavily on the grommet or carboy bung and made a tight seal..but the cheap ass plastic ones, especially the 3 piecers are NOT reliable for that sort of thing...If the CO2 out gassing is not that strong, it's NOT gonna lift the middle bubbler, but that doesn't NECESSARILY mean the fermentation isn't happening, the yeasties could be just as busy as bees and for whatever reason the CO2 is just sitting on the surface, or sneaking out elsewhere.
The yeasties still have a lot of work to do...just leave it alone for a couple more weeks and all will be well. If you are really nervous after 10 days take a hydro reading...