As have already been said, for a buyer to find your 3 images in an ocean of 19 millions is like finding a needle in a haystack. Just keep uploading your photographs, sales will come slowly. Lycka till !
Your portfolio exposure is you number of files vs the 19 million on line. So odds are slim and none that your photos get noticed.
If you are not doing it, start using the social media (Social Hub) portion of the site as well. When you upload a photo to the site and its excepted, hop over to Social Hub and have it post those new files to Facebook and Twitter. You just never know who you are connected with on those mediums that need stock photos.