As far as I know she hasn't taken a drink yet so dehydration would definitely make sense. I'll try soaking her today and see how it goes, I don't want to stress her out too much.

She is even more alert today. She slithers around in my hands and tries to flick her tongue at normal intervals (forks are still stuck together). Her movements are not jerky or odd (well no odder than her normal movements, as she is a spider). She isn't at 100% yet but the amount of improvement vs when I pulled her limp body from the tub is astonishing... I think I may have got her out of the heat just in time, that or she is far hardier an animal than I first believed. I'm trying not to get my hopes up yet though!