I Have Just Started Taking Metformin For T2 Diabetes Only

i have just started taking metformin for t2 diabetes only 250 mg dose for a week. my morning sugar was 7.5 and the ave for the 3 months was8 so my gp said to try it. i take blood pressure pills and cholesterol as well. my heart is pounding now and i feel it could be from the medication . i am 60 years of age and exercise at the gym. slightly o/weight.