Brief Answer:
Read below.

Detailed Answer:
I read your question carefully and I understand your concern.

Daytime sleepiness can have several causes, but sleep apnea is by far the most common one. So since you have been diagnosed with that condition it is important to determine whether it is a question of sleep apnea not being sufficiently addressed or whether there is another cause. As it's quite improbable for you to have two sleep disorders at the same time I would deem the first possibility by far more probable.

I understand that you use your CPAP regularly and that you sleep 7 hours a night, but I wonder how sure you are of that. Many sleep apnea patients are not aware of their night time apnea and awakenings. So while 7 hours, if of quality sleep should be enough, I wonder whether they are hours of really quality sleep. For that reason I suggest a sleep study should be done. Perhaps you have already done once it when you were diagnosed. It would determine whether the CPAP really provides 7 hours of sleep or if the problem persists.
Causes for the therapy failing might include weight gain, insufficient titration pressure of the CPAP machine, taking some other drugs which cause sleepiness.
Also other factors which can induce sleepiness should be considered like low thyroid function.
If CPAP is failing despite none of the above being present, then the use of oral appliances or airway surgery is the next step. Surgery can also be an immediate step if you have some airway abnormality like enlarged tonsils, nasal polyps etc which can be at the root of sleep apnea.

If excessive sleepiness persists even though the above mentioned causes for treatment failure and you seemingly getting 7 hours of sleep then stimulants may be used to treat excessive daytime sleepiness, like modafinil or armodafinil.

I remain at your disposal for further questions.

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