If you wake with a dry mouth, it suggests you are a mouth breather, not necessarily dehydrated. If you are a mouth breather, is this because you have breathing obstructions if you try to breath through your nose ? Could you have Obstructive Sleep Apnea, too? Sleep apnea will make any PCS symptoms much worse and will even cause PCS like symptoms.

You are vaping far more than you need. CBD has a half life of 24 to 48 hours. It stays in your system a long time. THC stays in your system even longer.

All the research suggests that the therapeutic level of CBD does not require frequent ingestion. Vaping gives the best absorption so you should have plenty in your system with twice a day dosing.

Your constant need to vape suggests to me that you need help with anxiety. THC can cause anxiety, even at low doses because it accumulates in the body quickly with frequent use.

It would be interesting to get a THC blood test and see how much is in your system. I bet it is quite a lot. This could be seriously contributing to your anxiety levels.