Try not to worry about the sleep test, and look at it as the first steps to a happier and healthier life.
I had one about three weeks ago, and to be honest I would say it's one of the best moves I made, as its allowed me to finally figure out why I wake up with a headache every day, why I couldn't concentrate etc. I have started on therapy and it's made me feel so much more energetic, and gives me far more clarity in my daily life.
One of my favorite sayings is that 'nothing worth having, ever came easily' and the journey into sleep therapy and CPAP, may be tough but the rewards are amazing.
I'm sure you'll benefit enormously and like me you'll wish you had it done years earlier.
Good luck and look for the positives, coz they are there.