Need some insight please, Bread sensitivity ?

So background first, I live in the UK and am type 2 diabetic... up until 2 days ago I was feeling fine, Managing my T2D through careful eating and stupidly decided to "treat" myself to some store bought crunchy white bread rolls... big mistake.

Blood sugar sky rocketed to the point I got slurred speech, Blurry vision and dizziness, Went to hospital and they did various scans for stroke, Zero which was good, Gave me water and just kept me in until I was well enough to come home, Came home feeling much better and a nurse visited me, She took my bloods and said my blood sugar levels were too low at 5.5mmol/l or 100 mg/dl, She said to have 2 x pieces of whole meal bread which I did, 1 hour later after she was gone all the previous issues come back, Blood sugar spikes again to 13.9mmol/l /or 250mg/dl, Still not feeling great but a little better but exhausted.

I thought with it being wholemeal it wouldn't spike my blood sugar, Can someone just have an all round averse reaction to bread no matter if it's white or brown and it should be avoided at all costs ?

Any insight would be greatly appreciated.