AGH! Missed scholarship deadline; what do I do?

Call the Admission Office or the person who first made the offer. You simply don't miss a deadline. Also, I do not understand how you ever thought there was such a thing as an application without deadline? Didn't it show up on your CommonApp to be a missing doent? If you had truly an impressive PSAT score and were in the finalist, maybe they will give you the scholarship. Maybe. If you decide to go to other colleges later (don't worry sweetie, you can get to colleges later if you're determined to. Take a gap year, if you have to and try for even better colleges) maybe you should use collegeboard.com; they remind you when the deadlines are approaching. Good luck, sweetie! Don't give up. Call them right now and tell your story you have written here.