GB is an autoimmune process... and some people can have a slower variant of it.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3152164/

Because it is uncommon, many physicians never see it and miss the diagnosis until the patient is in big trouble breathing.
My friend had plasmapheresis because IVIG was not available back then. She was hospitalized for 2-3 weeks and had PT for 3 months. She had just finished chemo and surgery for breast cancer, and about 2 months while recovering got a virus. She was in her early 40's then. I watched with horror as she became weaker and weaker and I called her husband who was in Wash.DC and he rushed home and took over-- deciding to put her in the hospital.

If they don't put you in the hospital, I'd try to elevate your head/chest off the bed so you can breathe more easily.