Not washing your hands after going to the toilet was called disgusting by your classmates.

They just want to make you laugh, so they will talk about you whether you wash it or not. The key now is not whether you wash your hands or not. Either you ignore them and don't take their ridicule to heart, or you find them and have a good talk. In fact, they meant no harm. Everyone is just classmates, and I have such a situation around me. Finally, pay attention to hygiene.