While I didn't suffer from diagnosed depression prior to *PAP treatment, it would only seem reasonable to assume one would. The severity would vary with the individual.
Your body is suffering from sleep deprivation, which results in all kinds of stresses being placed on the normal bodily functions. This is but one of the severe side effects of sleep apnea, which could lead to death.
The fact that your system can't properly rest along with external stresses, just compound the situation resulting in a vicious cycle, which continually escalates. Your mind is constantly running in different directions.
I am interested in hearing why *PAP failed with you.
Does it improve post surgical? You can do nothing but hope and pray. If it relieves the ill effects you are currently suffering, I would say you should see a reduction in the anxiety level. Sleep does relieve stress.
A positive mind set going into the procedure will assist you in handling the stresses. Talking with other helps calm the nervousness you are suffering. Handle one crisis at a time.
Everyone here has an ear to lend and a shoulder to cry on. We might even throw our 2 cents worth in to help.
Please keep us updated. You experiences always help someone else who may be walking the same path.