@Bow two things can be true. You can hold space for understanding her reasons, but still feel abandoned and let down. It is the whole 'I'm not mad at you, I'm mad at the situation' thing.
We have been socialised within a punitive justice ideology - which basically means that at every level of society, when there's a conflict of any sort (and I don't mean verbal, I mean like conflicting needs) then there's a 'problem' and that means someone is automatically at fault.
Since you know it's not her fault, your brain defaults to it being your fault for feeling upset. But you have every right to be upset - doesn't mean you automatically are blaming or letting her down by having that reaction.
Hmm... guess you can 'feel it out' a bit when you meet them? Maybe you can get away with writing out some notes, since they're unfamiliar. Bit of bg info (and anything you find difficult to share openly, but feel it would be helpful for them to know) and like, what you find helpful/unhelpful for support. Like I know you struggle to find your words, so you could request that they give you lots of prompts for sharing and stuff.
