Jess, Rather than seeing a neurologist, can you get an appointment with a therapist who can help you with your anxiety? Your mind has memorized symptoms from the past and is replaying them as your anxiety increases.

Yes, the neuro will likely just diagnose concussion. There is very little the neuro can do except refer you to people who can help you endure. You may benefit from a vestibular and visual assessment. That can be a cause of dizziness.

You should be spending your day upright, not in bed. You need to be doing things during your day to keep your mind active with low stress tasks.

Feeling dizzy or even nauseous when moving from bed to standing up is not a big deal. I've lived with that for 2 decades. I learned to move slowly when getting up. Once up and settled, I do fine.