Have to agree with Bob. My husband was switched from Atenolol to Metoprolol and he is also Diabetic yet it hasn't affected him. I have read that both those meds. can raise your BS and even though it may not affect everyone it's a possibility it may be affecting you for some weird reason. Maybe you should ask your Dr. to switch you back as long as the Atenolol didn't bother you and see if it stops. What may not bother one person just may bother another.
Good luck and best wishes...JJ....