I think you should do whatever you want to, really. I think most of the people on Wattpad that are writers, too, completely understand how you're feeling. If you feel like taking the story down is for the best, you should do it. I don't care this has become a sob-fest, everyone needs to let go from time to time.
Remember you write because you love it, it isn't supposed to bring you down. :)
I just wanted you to know that are people that love the book. It's easy to focus on the criticism, but there are people that love your writing. I just wanted you to know that, that's all :)