I don't know... you give her exact words, but not yours, so it's hard to say how easy/hard it would have been for her to misunderstand yours.
Text messages are so easy to 'not quite get'. Even if they seem to be crystal clear to the sender.
Even if your message unmistakably got across that you had an upsetting experience AND that you were looking for empathy (which is not always the case you know - some people are looking for someone to help them shrug something off, or to make light of something, when they convey something that happened to them) - even then, her replies could be interpreted differently than you did. 'How did you manage that?' And all the exclamation marks, could be interpreted to say that what happened is very unexpected, highly unusual, not in character. It also solicits more information. Ergo it shows that she does care, and is asking if you want to talk more about it.
'Lucky DS didn't see' could be interpreted as her, seeing how bad it all is, looking for any good part of it. Recognising how bad it was - if it wasn't bad, why would it be good that DS didn't see? At least that, she is saying. Trying, perhaps, to help you get through this/over it, by focusing on the good bit and bringing your attention back to your DS. Not saying that's what she meant, just saying it might have been.
Anyway, I don't think she will necessarily bring it up when you meet. If a) she didn't realise how distressed you were, how should she have realised meanwhile if you don't tell her? If b) she was trying to convey empathy and all, how should she know you misinterpreted her texts/didn't feel she showed enough empathy, if you don't tell her? Only if c) she really, really didn't have time, didn't feel capable at the moment to respond more at length, despite feeling she should have, only then would I expect her to bring it up 'Oh btw I'm so sorry I couldn't call last week when that thing happened in the bus, it sounded horrible, how are you now?'
Btw I'm really sorry about what happened to you. It can be very distressing to be assaulted, it kind of makes you lose your ground from under your feet. It's something that you just don't expect to happen, and when it does, it makes you question your assumptions about everything. Hope you're dealing with it ok. But really, texts are not the best way to convey feeling upset about something.