Yin,
Been following your journey - so sorry to hear of the BU decision. For whatever it's worth, I thought I'd add my two quick cents.
Meridion is right - you can't really control the outcome of your GRE. It is what it is (unless you take it again, that is). That said, you can control the other portions of your application - the communique with the department/professors, choosing programs that "fit" you (I think that's huge - the majority of applicants are all well-qualified; the question is whether or not an applicant really fits well into a program. By becomming familiar with programs, you can figure out which ones fit best and thereby increase your chances there), and, of course, refine your SOP.
Again, I gotta agree with Meridion - although I was lucky to do well on the GRE (or, as I like to put, I gave it the kick in the pants it so deserved;), I really feel like the clincher in my apps has been my SOP. It showed a lot of self-analysis/udnerstanding, spoke to the sorts of questions a adcom member might ask themselves, and (if I do say so myself) spoke with a voice. It was human, not just a list of accomplisments as though to say, "Here, I've got great stats. Accept me."
Most of all, and this one is probably the hardest to say without sounding trite or cliche, but you just have to remember, Yin, that you are a brilliant, valuable individual whether or not some program accepts you. Whether you had gotten accepted to all your programs or none of them, it doesn't change who you are. And I have a sneaking suspicion that, if not this year then definitely in the nearer future, you'll find yourself invited to a grad program that is absolutely perfect for you.
That said, best of luck! (and, enjoy the cheesecake:)