I am not sure if it’s gluten or not but I would stay away from it. I felt the same as you, kind of a sensation in my head and was sure that I was just getting anxiety over the test food. I kept eating it. In time I started having problems with my muscles, neurological issues etc. At first I thought it’s die-off, but as I cut out all antifungals and these symptoms persisted and kind of just persisted with different intensity but not going away, I am pretty sure it’s food reaction and now I am trying to figure out what it is. I cut oat bran out trying to determine what it is. I used it in my bread as well sometimes I would feel the same eating the bread. So I had to cut out buckwheat also to see if this is what it is.
FYI I had the same response with organic one imported from Germany.
I did not test as gluten sensitive, but perhaps I developed that a bit later.
You decide what to do and if your symptoms do get worse or you start getting other unexplained symptoms, I would be careful about it. I was of opinion that food sensitivity would come as hives, diarrhea, sneezing etc, but apparently it could come as any other symptom.