Chances are, after 7 days, you're likely done fermenting, but I would check to make sure you hit your final gravity range before considering doing any dry hopping. You don't want to dry hop during an active fermentation as a lot of the potential aroma you would otherwise get drops out due to the yeast actively working to ferment the wort.
What I'll typically do when dry hopping, especially if it's a hop combination I enjoy a lot of, I'll double up on my dry-hopping schedule. I'll get twice the amount of hops, split them in half, then dry hop the first batch for seven days. After seven days, I'll take out the hops, and put the second half in for another 7 days. After that, rack it off into bottles or kegs. This may not be ideal for all use cases, but I love an intense hop aroma, and cycling through two dry hop rotations really does amplify the aroma.
As it's been said above, 2-3 days is too short, and 14+ days with the same hops is too much.