My son has had is flu jab a fortnight ago his sugar went high for a day or so then they settled on Saturday his sugars went up to 20-22 then sSunday night he came down with a cough toke him to the gp when he wascheck over turns out he as a slight chest infection he was only diagnosed in August first illness is this normal to have such high blood sugars he as been like this since Saturday finding it really hard to get his sugar down