Airlock activity is associated with the most active phase of fermentation. Generally once you pitch your yeast, there will be a lag phase where the yeast is assimilating to its new environment and starting to grow and multiply. Next is the active fermentation where the yeast is going wild chomping on sugars and excreting all sorts of good and not so good byproducts. What you seem to be in now is the clean-up phase where the bulk of the sugars have been consumed and the yeast is busy at work scavenging up many of the by-products they produced. During this last phase, the airlock activity may be very low to almost non-existent.
Unless it is a low gravity beer (OG less than 1.036), I expect that the total time in a fermentor should take a minimum of 10 days. Depending upon the variety of yeast used, there will be a 4 to 20 hour lag phase, 2 to 4 days of active fermentation, and the rest being the clean-up phase. I allow by standard gravity brews to ferment for 13 to 15 days, higher gravity brews take longer. Following that, I cold crash by lowering the temperature slowly over a few days then allowing the carboy to sit for 3 to 4 days at 40F to 45F to allow the bulk of the yeast to settle out.
For the most part, patience is almost always rewarded.
