I've always had low blood pressure, which suddenly got higher. The Doctor said it might be white coat syndrome, where just being at the dr's makes it raise. But to be sure he put me on the 24 hour monitor, apart from being a bit uncomfortable in bed it was ok. My bood pressure fluctuated within the 24 hours, went up to 180/ 90 and down to 127/ 68 over, up and down all within the 24 hours. Although higher than it's been all my life now it's still within normal limits. I would suggest you accept what the doctor has offered and go for the 24 hour monitor, hopefully it'll put your mind at rest.