Depending on your setup, airlock activity can mean a lot, or nothing at all. A carboy with a snug stopper will *probably* give a somewhat accurate account of what's going on. A bucket might never bubble at all, due to leaks in the seal. Or it might bubble some if the fermentation is going faster than the leak can allow to escape. Then once the fermentation slows down it might stop altogether as the Co2 can now get out past the seal again.
Also, change in temperature can cause Co2 that was once in solution to come out of solution and start the bubbling again. This generally happens when the fermenter goes form colder to warmer, or if the fermenter was bumped.
I think the important thing to know is that fermentation HAS TAKEN PLACE. Now it's up to you to find out when it's finished so you can package your beer. Take gravity readings and when the stabilize over a couple of days, you can bottle if the beer is clear enough for your personal taste.
I usually do 2-3 weeks if I'm not busy with other things. If so, it doesn't hurt to wait a bit longer. Some people even rack to secondary for some reason.