I had high blood pressure reading once when I was donating blood. Something along the lines of 133/80 or something like that. I had my reading done laying down and the cuff on the left arm so it was all wrong.
I bought the Omron-machine above like 2 years ago and I check BP once every two weeks or every month. I’m usually at 100-110/60-66 so really not in any danger zone at all. Which I figured that’s why i bought the machine when they gave me that weird reading.
I’d recommend buying a good machine and doing readings at least twice a week for a month or two to see how it really is.
I usually do my tests in the morning after weighing myself and going to the bathroom. Always sitting in the same chair and in the same position and arm, right arm.