Forgive me if I'm making a false assumption here (EDIT: it turns out I was), but I don't think you have a real problem. I think you believe you do because you've been told (or have otherwise decided) to avoid the passive voice where possible. I think this is a mistake.
Writing "rules" are really little other than "things to watch" while you're writing. As evidence of this, open your favourite book (or anyone else's favourite book). The odds are you'll find plenty of examples of "universal writing rules" that have been broken.
Where the rule is "use active over passive voice", interpret this instead as "be acutely aware of whether the voice you're using is passive or active". The point is to use the form that's the most appropriate, and produces the desired effect. Since many people write books of a sort where the active voice is the best choice pretty much throughout, people who read and like (and probably also write) these sorts of books have over-generalised and assumed passive is always bad.
It seems to me though that in your case, in this particular scene, passive voice is exactly what you need. The character doesn't feel like things are being done, she feel like things are happening to her. If you want to put the through that experience with her, using the passive voice is a perfectly reasonable way to do that.
ADDED IN RESPONSE TO THE ASKER'S COMMENT:
As for ensuring variety, or having more options that just the two, I think the issue is that at a fundamental level you really only have the two. You don't know (or don't want to reveal) the thing that's responsible for the doing, so either you make note of what's done without (or with only oblique) reference to the thing that does it, or you say that something did the thing without saying what. I think those are your choices.
What you can do, though, is disguise it a little by varying the language. "Something poked her shoulder", "an object poked at her shoulder", "she had no way of knowing what or who it was that poked her shoulder", etc..
I would say though that if you're repeating the same idea over and over (in this case that something she's not lucid enough to comprehend does some thing she's only vaguely aware of) you're likely to run into repetition issues regardless. The issue might not be to do with how you word it so much as what you're saying. (Note: I'm saying that is the case; it's just something to watch for).