The adjustment to CPAP is often stressful. After all, we've been used to sleeping a certain way for a very long time. Our brains truly resent any deviation from the norm. For those who have a history of GAD, GAD recurrence could certainly happen once CPAP treatment is started. I'm sure it has likely happened to others. Have you checked in with your doctor about this? If not, please do so and ask if he/she would recommend a change in medication or dosage to help you cope right now.
It takes time, patience and persistence to adapt to CPAP treatment. For the fortunate few, the adjustment takes place in a day or two. For most others, it takes anywhere from 2 weeks to 6 months. The time period is shortened for those who commit to sleeping with their CPAP at all times. Here's the reason why...our brains will interpret any repeated stimulus as "normal" and "expected", if that experience is repeated over and over again. Also, if the stimulus is repeated in the same setting, (nighttime, bed, covers, sleep), our brains will come to expect the stimulus every time we are in the associated setting. The setting itself leads us to expect the treatment which then brings relaxation, repose and sleep. It's an "ah" moment and from then on, we can't even imagine sleeping any other way than with our CPAP. It's just what we do at night. The trick in getting there is in over-riding our brains' initial natural reaction and in sleeping with CPAP anyway, over and over and over again. Convince your brain that CPAP is your very best friend.
The CPAP pressures keep our airways open so that our tissues and organs can be oxygenated. The health rewards of CPAP treatment are almost too many to count. We'll get to experience a longer life and better quality of life along the way. It's worth everything we do and pay to make our treatment comfortable and even pleasurable. There are lots of tips on how to do that here on this forum.
So, hang in there, friend. There are better days ahead!