My wife was diagnosed with sleep apneoa over a year ago.
It started with a questionairre with questions like "do you fall asleep whilst you're a passenger in car?" which she answered yes. (Very subjective 'cos we were answering in the context of 12 hour trans-Europe drives, where she'd fall asleep whilst I'd happily drive the whole way).
This lead to a sleep study (monitor overnight)which revealed she was stopping breathing a few hundred times every night. This was a bit of a shock as it wasn't causing any sleep loss and I'd never noticed – but yes she was a snorer.
Once diagnosed, she got the CPAP immediately, which was fortunate because you are obliged to inform DVLA of the condition and you need to be able to say that you are receiving CPAP treatment or there's a strong possibility they'll say you cannot drive!!!
She was on the CPAP for about 8 months and to be honest lost more sleep as a result of its intrusion than she'd ever lost through sleep apneoa.
During this time she went on a diet and managed to lose a couple of stone. This had a dramatic effect and resulted in a follow-up sleep study revealing that she no longer had the condition. Machine returned. DVLA happy.
Bottom line / personal conclusions:
Whilst the condition never effected her ability to drive, the diagnosis felt like a slippery slope towards losing driving licence.
Weight loss worked.
CPAP machine was a nighmare.
I hope this little story inspires rather than alarms.
Good luck with it.