I do not know if it is GBS or CIDP. What I do know is that your initial experience with symptoms and treatment or lack thereof sounds very familar.
To make a long story short, 1969 my CIDP (DIAGNOSED AND FIRST TREATED IN 2004) began with the dizzy spinning feelings that grew increasingly violent over 30 plus years until in 2005. With the infusion of IVIg the spinning on March 5, 2004 was 24/7 and the infusion stopped them confirming the CIDP diagnosis. Along the way there was the , pain and weakness, tingling, and numbness in left arm, left scapula, fatigue, weakness, shortness of breath, very short periods of temporary paralysis, in the 1970’s. No diagnosis…every test seemed normal…except VERY SLIGHT change in reflexes that were dismissed and several misdiagnosis that were used to dismiss a neurological condition.
1980’s the electric shocks began in left side of neck, left arm, fingers, left scapula and chest pains. (This one side development was not characteristic!! and it took another two years before the other side of the body began to show symptoms.) All tests were normal. A lot of tests were never run. Pain increased until they realized many years later that I had partial paralysis in the left side of neck. The in mid 80’s the numbness in feet and legs started and right arm affected. Weakness was great, loss of stamina horrible.
What I am sharing is that most all tests were normal and all kinds of things were ruled out but no one diagnosed my neurological disease until in 2000. By this time I had became very disabled and the remitting and relapsing pattern of my symptoms drove me and the doctors crazy. Only and I repeat only with the IVIg was my diagnosis confirmed as CIDP and I responded in miracle ways. (Got out of the wheelchair)! One clue here is that with the slow progressive development of my symptoms, unlike the little I know about GBS, this type of development was more characteristic of CIDP.
Finally the reason a trial of IVIg was given was an article by Dr. Norman Latov of Wells Medical College Cornell University NYC that talked about the difficulty in seeing damage to the nerves in some types of CIDP. What I have learned above all else is that these conditions present in a LARGE varity of ways and often do not fit the text book of the doctors training. The doctors need to think outside the box in looking at your case. Often neuromuscular neurologists seem to have the most knowledge here. If all your tests seem normal and they have ruled out a lot of possible causes, this is exactly the path toward the diagnosis of CIDP. It is often diagnosed by what is not wrong. Frankly with a slight or any change in protein and given your symptoms, some form of a neurological condition would be highly suspect.
Wish you well…and hope you get a diagnosis and treatment.