The consensus is to rest for the first few days then slowly introduce activities that do not cause an increase in symptoms. If going for a walk/exercise causes an increase in headaches, don't do it. If listening to loud music causes an increase, don't do it. And so on.

A neck CT is meaningless to rule out an upper neck injury. They are very subtle. They are often diagnosed with manipulations. If there is a tenderness behind the ears, that indicated a possible neck injury. The treatment is an upper cervical chiro or gentle but skilled Physical Therapist or osteopath. Most garden variety chiros are too aggressive. It also requires discipline to sleep and rest with good straight head and neck posture for a few months or more.

I bet you will find that if you look back, the increase in symptoms have a trigger, especially the anxiety. The concussed brain often struggles to filter out visual and auditory stimulation. Over-stimulation can cause the anxiety, nausea, etc. Your body will be your best guide if you just take the time to listen to it and correlate symptoms with your activities and environment. It might help to get some foam ear plugs. "Macks" makes the best.

You sound like you are a details oriented person. Such people often struggle to recover because they are too symptoms focus. This can be a self perpetuating situation. Learning to let go can be very beneficial.

My best to you.