Malefor, let's put this into perspective. I know you've already been told, but I'm not sure you understand: how would you feel if somebody took your sprite, recolored it, and morphed it into their own? How would you feel if somebody took all of your hard work and claimed it as theirs? What if that person's more popular and gets more attention to their sprite, which is actually yours? What do you think that feels like?
It feels like !@#$%. Complete, and utter !@#$%.
Equally, how are you going to be a credible spriter if you don't do your own sprites? What happens, one day, if you actually get a job in the real world but you only managed to make a portfolio out of frankenstein sprites that aren't even yours? You're going to fail at your job, and you're going to fail hard because you wasted these learning years by taking other people's work. You may use other people's work as inspiration but come on. Let's not get too far.
Please, please, please. Let's not get into another one of these situations with you. You have potential and so much spark that it truly is a waste to see you crumble.