Sorry to hear you are having such a bad time. Plasmapheresis usually starts working by about the third or fourth treatment I was told. I started feeling better on the third day. Ivig did not do much for me either. Are you on anything else like prednisone?
I found that the prednisone made me worse, but that is me and we are all different. I started back on plasmapheresis yesterday and can tell the difference. It is what keeps me swallowing enough to stay out of the hospital.
Hope something starts working for you soon.