I know how you feel, my skills test was cancelled...ready for this..........23 times. First booked in Oct 09, finally complete Sept 10. Bad weather every time. Inbetween bookings the weather was great, but when I booked a test, the weather closed in EVERY time.
My first skills test was even called off half way through due to lowering cloud base. It added alot more hours to my log book, and removed a few more zero's from my bank account.
Stick with it, it's worth it in the end. It took me 2 1/2 years and 68hrs. Losing my job half way through didn't help either.