You should ask your doc abt this, not this general forum, cialis can affect heart function or ppl with high blood pressure.
Ppl with diabetes are prone to circulation problem when the disease progress to an uncontrolled level usually.. is your HbA1c ok?
One of the symptoms associated with progressing diabetes is erection problem.
Perhaps you might want to try R-alpha lipoic acid which is known to help ppl with diabetes for a better blood sugar management/prevent neuropathies, which theoretically and eventually would naturally help you gain back [the natural way] many bodily organ functions (although it may not be as when one is young, as male testosterone goes lower as they grow older)
Doctor normally monitor how good you are at blood sugar control (or the medication given is giving the intended benefit) by monitoring your blood HbA1c levels. Levels could also increase if patient is non compliant
This could be done by doing a blood test for HbA1c (although I think not all visitations would req a patient to do this, so perhaps you might want to ask your GP to take your blood at times for you to see it).
Cholesterol medicine lowers your cholesterol levels and since cholesterol is used by your body to make testosterone - your testosterone level will be less so your erections and desire will also be lessened - I speak from experience. Once I stopped taking my cholesterol medicine my erections came back. My cholesterol ratio numbers are fine - but the medical establishment posts rediculus total cholesterol guidelines because they don't understand that only the ratio matters. Get off statins they are bad for you. Use natural methods instead - eat fresh unprocessed food only and get regular exercise to increase blood flow.