The lumbar puncture will have an elevated protein level if you have GBS. You could either have a rather mild case of GBS, which could either work itself out on its own, or you may need some IVIG infusions.
If you keep getting better, than worse, you could possible have CIDP, which is chronic, but usually very treatable. The only way to tell (other than getting a sural nerve root biopsy) is to see how the disease progresses. If it goes away with treatment, it is GBS. If it keeps coming back, it could be CIDP.
And no, you are not imagining any of these symptoms. I am so glad you are seeing a neurologist. BTW the MRI was probably to rule out MS, they were looking for lesions on the brain I am sure, which they must not have found.