One thing you will discover as you brew more and more is that patience is most definitely a virtue. I remember what it's like... you brewed your first beer and you are so excited to know how it came out!
Airlock activity is not an indicator of fermentation rate... but I generally use the airlock stopping to bubble to indicate that fermentation is entering it's final stages.. .after that it's all about gravity readings and getting a couple of consistent readings on consecutive days. That's your good indication that fermentation is done.
So, where you are after 7 days, you may consider the following...
- Give your fermenter a bit of a swirl. People have different opinions on this "rousing of the yeast" but I always like to do it.
- If you have the capability to... up the temperature to the top of the optimum range
Both of these give you a chance to have the yeast finish up it's job, particularly in terms of it munching through not only the fermentable sugars but also some of the by-products of fermentation (cleaning up after itself).
Even after all of the above, you might want to still leave the beer in the primary for a week at least. Particulates will drop out of solution to give you a clearer beer.
Even then, it might still not be time to bottle. You might want to cold crash the beer. Again, particulates including yeast will drop out of solution as a result giving you a clearer beer. (You may not have the means to cold crash a fermenter full of beer so you may do this later in the process after bottling and once you've given the bottles time to carbonate).
Patience, patience, patience lol... in the worst case you could bottle your beer before it has finished fermenting and end up with bottle bombs!
You will not harm your beer by leaving it in the fermenter for an extra couple of weeks...