Call them! Don't wait to be called. Take the initiative. If the sleep lab that you were referred to can't get him in quickly ask your doctor for the name of another lab. There are usually several in every area. If that doesn't work, contact a dentist in your area that treats sleep. They can usually help.
So the good news is that even if you have central apnea, a C-Pap machine will help. If you have obstructive apnea you have multiple options for treatment besides C-Pap. As young as you are, your options are probably higher than someone in their 80s. Central apnea is rare but treatable. Don't lose sleep worrying about what you might have.
I have had the Nightlase procedure done on me. After the procedure was done I had a follow up in home sleep study and it showed that my O2 sats were much higher. I had been dipping to the low 80s and after Nightlase I never fell below 90 and my AHI went from 28 to 9. I would consider that an excellent success! And my husband says I no longer snore. I was unable to wear a CPap and had gone with an oral appliance from my dentist. That was successful as well, but when I heard about Nightlase I was excited to learn that I no longer had to wear an appliance every night. The procedure was easy, painless and quick.
If you don't succeed with the C-Pap machine there are alternatives. Most providers will not tell you about them because they don't provide them. One of the alternatives is an oral appliance that you can get from a dentist that specializes in sleep medicine. Another alternative is a laser procedure called Nightlase. According to sleep physicians the CPap is the "gold standard" but there are so many people who can't use it that it is important to know that there are alternatives and where to go to get them. Let me know if you have any questions about either of these procedures. I have had both and have had excellent documented success with both.