For 3 days I have had serious vertigo that only occurs when I am lying down and turn my head or try to sit up. It goes away quickyl once I am able to sit up carefully or lie still. It did happen once when I was installing something overhead and had to be looking up for an extended period. Blood pressure appears normal and I have had a pace maker-defrib for years from an old diving embolism. I am an otherwise very healthy male , 87 years. Should I seek care, and if so; my GP or cardiologist? This is a holiday weekend and my normal care-givers are not available.