Yeah, I personally think most all drugs have some kind of side effects that are likely to wind up being permanent, even after you stop taking them.
I used to take Hydroxyzine, too.
It was great while it worked but for whatever reason, it just stopped working for me. My doctor put me on Ambien, where you have to show ID and prove who you are and that it's you when you pick it up. I'd never experienced this before, so I felt like I was wanted by the FBI or something, lol.
And I hated how it made me feel. I vaguely remember some Winnie the Pooh cartoon in which the narrator is reading the actual book, then turns the page -- and all the words start to slide off the page. That's exactly how my brain felt when the Ambien was kicking in, and I was like, "Yeah, ok, I am NOT going to take something that makes it feel like my brain is melting!"
But I still wasn't sleeping either. Funny thing, my regular doctor was out of the office and another doctor stepped in for my follow-up, and she's the one who gave me this literally life-changing information.
I'm sure it was God -- and I hope He leads you to something that works for you, too!