Well, by 'walled off', I mean that I was stuck in control of the body, and able to only see and use a smallish part of the collective mind. It sounds like you might be a bit blocked off, but possibly not as much as I was.

Being 'cut off' had nothing to do with physical harm. It was just my words for describing how I couldn't feel the others. I also have a chronic illness, so I sympathise with the anxiety of that...I would think that any physical illness is affecting the body. The stress of being ill belongs to whoever is in the body at the time, I'd think. I wouldn't worry about it being 'not of you'.

'Ghosting' was what I use to describe the feelings of the others trying to contact me. I would get tactile hallucinations (hands touching hair, etc), sometimes hearing voices, or getting flashes of imagery, particularly in the dark. Just the presence of people. It was rather scarey and drove me to panic more than once.

If one of your group has been emailing your friends, then I'd say they probably do want to talk to someone. Maybe try leaving notes out for them, or starting a communal book or computer file? I agree with Gharveyn that resisting what's happening isn't really worth it. If they're there, then they're there. I had to learn that one myself. It helped a lot, for me and everyone else in the group.