On the bright side, your chances of getting in are ridiculously small anyway, right? The interview will be good practice. Look at it that way. Take what you can from it, and chalk up your mistake to a lesson learned. Hopefully you applied to a range of colleges and you will end up where you are supposed to be.
And what do mean about it being the only college you applied to. You said you applied to Harvard and already have a couple of UK unis lined up.