I really feel like I enjoyed not helping her
It sound's a bit mean. Did you stop yourself from helping her?
Yes, I did. My friend didn't finish her essay and she needed my help on that.
I don't understand what kind of satisfaction you can possibly get out of this all, but you do you. It's cruel though, that you were perfectly capable of helping your friend but you still didn't. You shouldn't be friends with her if you don't want to extend your kindness.
You don't think it was funny? I was watching her panic. It was quite fun.
It sounds like you were being a bit of a bully there. If you were her, you might not find it funny. So maybe don't mistreat her because she is nonetheless your classmate and friend, and it is expected that you help out your friend.