"I'm not sure what to do, where to go or how you'd like me to react." Or more simply: "I don't know".
My interpretation of the palms-up shrug is not "what?". It's:
1) so what?
2) Whatever you're asking me could go either way and I could not care less.
3) I really couldn't tell you what you want to hear, so why are you still staring at me? When I do that gesture, I think of myself handing off whatever is in both of my palms. "Here's your sword or baseball bat or muffler, dude. You want it to be a priority? Then it's yours and not mine. Leave me out of your drama." You're tossing the load, not being confused.
No, I don't. If the person does it as if to walk away from a conversation, I get angry. If the person has provided some information leading to the point of the palms-up shrug, then I usually understand that the person is at a limit and there is no point in being angry.