Hello Kab65
It's is possible that you may have a virus, or if you torrent files they could be "Seeding" (uploading) information in the background constantly. It's usually rare that your uploading would exceed your downloading through normal usage. I'm comfortable with computers but not as intimately familiar as some of the other users of the forum would be. At least it's something to check for in the mean time.
Hope this helps. 