Has the sleep apnea test been ordered? I'm not sure why they won't do anything until that's done, but If that's the case, I'd want to get it over with asap.
First of all, you aren't "sure" that you have cancer, second, there are different types and stages of cancer, all with differing prognosis, but usually once the thyroid is removed, the cancer is gone, too. Thyroid cancer is usually slow growing.
Hard as it may be, you need to get through the biopsy to find out if you even have cancer, then take it step by step.
I know it's easier said than done, but try to relax. Anxiety always makes things seem worse.
There is a forum here on Med Help, specifically for thyroid cancer. You might want to check it out. I've provided a link to the home page.
http://www.medhelp.org/forums/Thyroid-Cancer/show/1199