Yes, you definitely did not make a swastika! You made a windmill! And windmills are good. Do not give evil the power to spoil your pleasure in creating something beautiful. As cybrarian said, that symbol has existed far before it was adapted to represent one political force and will exist far after that force is gone. And your windmill does not have the extra leg the swastika has, as cybrarian also mentioned.
So love your potholder, it's great!