I predict that Revvy will soon show up with a ten-paragraph post about this, but I can sum up what he will say in a single word:
Edit: Okay, I'll say a bit more. Listen, YMMV, but for me, I have never had a beer stop making bubbles in the fermentation lock. Ever. I think that is unusual, and I can't say what it is specifically about my set up that causes this, but it just keeps bubbling for me, about once every minute or two, even after active fermentation has long ago ceased. The usual explanation is that it is CO2 that is already in solution from previous fermentation being slowly released.
If you're getting several bubbles per minute, that usually would indicate fermentation is still active, but even still, if it's been as long as you say I would take some hydrometer readings to double-check that. Take a hydrometer reading, wait 2-3 days and take another, and if it's still the same then it isn't fermenting, no matter what your airlock is doing.
I don't care if once a day your airlock transforms into a magical elf, leaps merrily off the carboy, dances a little jig and then climbs back on and turns back into an airlock. If the hydrometer says the beer is done fermenting, then it's done fermenting.