Nah, Vriska wouldn't do anything like that if you were just annoying her, but I can't speak for her myself since I haven't been to see her. From what I heard it sounds to me like someone wanted to cause trouble.

I think you should visit her, let her know how sorry you are. Because sitting on it won't do you any good. You'll just keep feeling guilty about it until it swallows you whole.

And you're definitely not a monster. Monsters are created, not little weenies like you.