M.R.
It does not seem strange to me, because we had a child this young with the disorder. It is chemical, they can't help it. If anyone moved anything in our house, she had to put it back, and she could not function until it was done. Drop of water on the dress, new dress. Could not eat ANY thing messy, and the fork could not touch her lips because she might get something on them, it was so funny to watch her eat.
Some of it may also be sensory related, mine had auditory defensiveness, and it was rough. A loud noise would spook her, and she might bolt and run. We asked for a handicaped sticker so that we could park in the best place for her, so that she was more safe if she bolted, and that was not always in the handicaped spot, but it was helpful to have. I had to choose between her (she was 3, and the baby who I had just strapped into the stroller, and I let go of the stroller because it would just roll into the curb and she was running for the street because someone started a lawn mower...left there and drove to the doctor and asked for the form to get the sticker!
I don't have many books to recomend on the anxiety, but you are doing the right thing by taking her to a psychiatrist. We waited until she could not attend Kindergarten, and so wished we had done it sooner. The medication made her feel so, so, so, much better. It was night and day. I have zero doubt that this is totally a medical condition after what we saw with her. She did not even need therapy, it was all chemical.
There will be medication doubters, but don't pay any attention to them. If they had a child in this much misery, they would understand, but they don't so it is easy to say that you would "never" medicate a child that young, or that medication should be a last resort. Do what you need to for her, and done worry one bit about it.
Ours is a typical 13 year old now. Still takes meds, we have had to adjust with age, as they change over the years and need different things. Her room is even a mess! She still eats a little funny with the fork!
Good luck!
M.