You know people spend countless hours sometimes on one piece, even days or more, not counting breaks. That doesn't even account for the years and years of study. Can I go into your home and take your things? I mean if I take something that's worth a hundred dollars and sell it off, it's still less of a theft than you stealing hours of blood sweat and tears from another person.
You should stop this before the law catches up with you. Seriously, think about it. What you're doing is absolutely corrupt and you are HURTING artists by stealing their hard work.
Maybe you never thought of it that way, with people just calling you "art thief" and leaving it at that. Remember something you worked really hard on, and now imagine someone stealing it away and selling it and giving you no credit. Wouldn't it just break your heart?
Please be a decent person, accept that you made a mistake (WE ALL MAKE MISTAKES!) and repair it before it becomes more than a mistake. Now you know better. No excuses!