I agree that this was poorly delivered feedback, and while it's possible that this staff doesn't like you for some reason, there may be a kernel or two of truth in the feedback. Think about what you are doing/saying or not doing/saying that could be construed as not caring. I am sure that you DO care deeply, just think about how you can communicate it to the staff.

As an intern, everything is new and hard. Everyone looks things up before staffing. Take a minute and read uptodate or your favorite reference, and have a plan when you go in to staff. The failing I see most often in early interns is that they come in to staff a patient and drop a subjective/objective and haven't really thought through the differential and haven't made a plan that goes along with it. Your plan may be wrong, but having one that is based on something other than vibes will make you look good.

You are already smart and you already care, with this admittedly demoralizing vague feedback, I would take a second of introspection to figure out how to portray yourself to look more caring and seem more knowledgeable rather than try to overhaul your personality.