Change in personality in my cat after I 131 treatment for hyperthyroidism.

My cat had a I 131 treatment for hyperthyroidism four weeks ago and since then she somehow isn’t the same anymore. It said that cats could seem off or lethargic etc. in the first two weeks after treatment but now it’s a little over four weeks already. She is much quieter (used to be extremely vocal before) but certain routine behavior changed as well, like she doesn’t come to cuddle anymore at bedtime or the morning, often doesn’t „answer“ anymore like she used to when „talked“ to. She is not spending time in her favorite bed during the day on the window and so on.
She does not seem sick to me, she eats very well, drinks normal, uses the litter box as usual and is still responsive an cuddles at different times.
I am just wondering if someone had a similar experience?
Next week she has her lab appointment so I wonder what the Vet will say.
Hoping she gets somewhat back to how she used to be before.