Keep your head up. I understand that this must be unbelievably frustrating, but this is only a minor setback. All of the practice tests that you took are good tests and are indicators of your real potential. The only thing to do is study a bit more and retake the GMAT.
Don't let it get to you and don't be discouraged. You have to look at this as an inconvenience and press forward. As the stated in the above post, you aren't the only person who has dealt with this.
Also, just out of curiosity, what happened? Was it stress?
That helped ..
I was not stressed at all. Reached the test centre on time ....AWA & IR went quite well . After that I took a break ..
I was confident that I will do well in Quant & Verbal. I had enough time to finish Quant & Verbal sections
Have never been weak in tests,scored 85 percentile in CAT(Indian MBA entrance exam) last year ..
I had hoped that to crack GMAT as well ...