Two weeks into fermentation isn't long enough. You need to let it ferment for at least another week, preferably two so the yeast has time to clean up after it self.
Huh? That's silly. Two weeks is almost always plenty of time. Take an SG reading, and take another one in two days. If they are the same, it's ready to bottle.
The "yeast cleaning up after itself" happens in the first 24 hours or so after fermentation slows and ends. It doesn't take three weeks, although no harm will come to the beer if you do leave it for three weeks.
A well made beer will be ready to package in about 10 days or so, depending on the yeast strain. A couple of keys- pitching the proper amount of yeast (most homebrewers underpitch) and keeping the beer at the proper fermentation temperature- means that the bulk of fermentation will be over in about 5 days or so. A couple of days for the yeast to do their clean up work, even digesting their own waste products, and then a few more days for the beer to clear a bit are usually all that is needed before packaging.
Some yeast strains (like S04 and nottingham) clear the beer well within a couple of days after fermentation ends so clear beer can be packaged at about day 10. Some yeast strains (like S05 and Denny's 1450) hang around in suspension for a while so waiting a bit longer for it to clear might be a good thing do do.
In general, I package my beer once fermentation has been over for at least a couple of days and the beer is clear or clearing. For most beers, it's by day 14.