being easter i cannot reach my gp.... however last evening i had sudden drop in BP with low heart rate. nitro lingual seemed to ease it a lot but after being fairly normal this morning it has occured again even with a trans dermal 50 on diastolic dropped to below 60 with pulse rate below 45.. I do not feel otherwise serious ill..
Nitroglycerin itself is the reason of your blood pressure fall, as it will dilate your arteries your diastolic blood pressure falls, avoid it if there is no chest heaviness Or exertional breathlessness.  However, I will suggest you to get an EKG done particularly when your heart rate is on lover side.  Likewise, if you are on beta blocker group of Chat Doctor.  Do re titrate your medication when your GP returns.  Regards.