Whenever I Eat Refined Sugar, Corn Syrup Or Cane Syrup,

whenever I eat refined sugar, corn syrup or cane syrup, I get listless, brain fog and down....almost like depression. My doctor says my sugar levels are good...no thyroid issues, no diabetes, no hypoglycemia. I stay away from sugar but often hidden in foods. I have celiac disease...no meds for that. Stay on Gluten fre diet...no cheating. I have a-fib. I take Metoprolol ER for A fib. I am 71 years old.