I’m really sorry to hear that, I don’t have too much experience with chronic anxiety but every few years I’ll have a full on panic attack just randomly and it’s absolutely excruciating, I can’t imagine having to live with that on the regular.
Just one other comment, I’m a bit wary of using antihistamines in general, probably irrational paranoia but there’s been some news that over the counter ones can increase risk of dementia later in life and hydroxyzine seems like it’s a lot dirtier and more powerful. For just passing out there may be other options, have you tried an alpha agonist (clonidine, tizanidine)? I feel like these are tragically underutilized as sleep meds, not everyone gets super tired but most do, and from personal experience at least the sleep quality is very good. Probably easy to get from the doc and I’ve never heard of anyone becoming addicted to these although there is technically now a street drug in this class (xylazine).
Unbelievably lucky for the eclipse, had a family gathering planned way ahead of time in Waco tx, some are older and anxious and wouldn’t have been up for a journey onto the roads to try and get out of the clouds. It looked like the sun would for sure be obstructed at totality, it peaked out a few times leading up to it but never for more than a minute. But like a hole opened up just as totality was reached and it stayed for 3 whole minutes. Actually I was happy for the bit of clouds at the end because the obstruction allowed my phone to capture the last 60s and was still plenty visible with naked eye.
Super cool celestial event, spectacular even, would recommend!