Hopefully, I can answer your questions clearly.
Normal ranges for A1c are 3.8 - 5% [60 - 99
mg/
dl], or 4.1 - 5% [70 - 99
mg/
dl] depending on the doctor. At 6% it equates to a daily average of 125 mg/dl, borderline diabetes by a very slim margin. By slim I mean that diabetes begins at 126 mg/dl.
That weird feeling you got when your level was 67 mg/dl happened because your body was accustomed to and adjusted to higher levels.