My bad... My intention was to build on your ideas, but I think I erased my new ideas before posting while only leaving yours.
So let me try again...
like cloutclout123 said, it is important that you contact YH before making any decision. Many schools may forgive withdraws, as long as you keep your GPA above their minimum threshold. So in that case, it is best to withdraw and work real hard in your other courses. That is what my friend did, and he is at Columbia now. Also, he did not tell Columbia before hearing from them. He only made sure that he would still be in the clear. He did not want to give them a reason to not accept him.
If you find out what Harvard and Yale's policies are, I would not mind helping you decide whether or not you should withdraw, and if you do withdraw whether or not your should let YH know.
@cloutclout123, I still may be repeating your original content, but hopefully I am bringing another perspective.