Unrealistic?

I think perhaps I've set myself an unrealistic goal.  As I've said before, I've been praying to get into my "wish dress," a dress I bought specifically too small, to wear at graduation.  (less than 2 weeks away now).  Although I have made progress--I weighed myself yesterday and have officially lost 21 pounds--I had my friend help me try on the dress yesterday, and she informed me that although I was close, it was probably impossible to get into it by graduation.

I have to say--I'm devastated.  Truly devastated.  It feels as if I've worked so hard for so many months, for what?  It's all very depressing.  I knew it would be hard, this dress is made only of cotton, so there's not even an option that it'll stretch a bit.  But I guess I just have to face reality and hope that one day this summer I'll be able to wear that dress as a nice summer dress.  For now though, I'm just exceedingly unhappy that I will apparently not be meeting my goal.