If your chiro is doing the twist the head and pop the neck adjustment, it may be too aggressive. For many it is. C-1 to C-2 and C-1 to occuput do not settle in like the lower vertebra do. The twist the head and pop the neck adjustment may help a lower level and traumatize the upper levels.

A gentler technique may be worthwhile. Gentle traction with mobilization or an upper cervical chiro technique (not the machine) or Activator with a follow up of icing can be good. My PT would first release the neck muscles with myofacial release then with me on my back, pull gentle traction and mobilize the vertebra. My outstanding Activator chiro was not helping me with atlas and such like he hoped. He sent me to the PT. She helped me immensely.

I had to change how I worked with my dogs. No leash jerking. And, I had to change how I scanned the yard for messes. I had to turn at my shoulders rather than at my neck.

The most important change was sleep position. I had to sleep with my head and neck straight. No pillow lift or head twist. I did best in a recliner until I learned to sleep on my back consistently.

You can choose to let go of the issues that you are hypervigilant about. It takes a lot of effort and maybe some CBT. You need to replace those thoughts with safe thoughts. The Celexa may help. It usually takes a strong dose to get the OCD help. Hypervigilance is a form of OCD. PCS often make hypervigilance worse. It did for me. Except, I would get stuck on meaningless thoughts that would exhaust me.

I was on an SSRI for 14 years before detoxing and replacing it with 5-HTP and the vitamin regimen, especially the B-12. You might want to consider 5-HTP instead of the Celexa. You can't take both.