I've suspected white coat hypertension. I have a BP monitor somewhere here at home so I need to dig it out and measure myself. I don't know if it's really accurate but it should give me an idea. I just know the last time I went to the Dr they took it once with the machine and when they saw it was high they took it manually. The manual measurement was slightly lower but it still made them concerned.
When I'm not at the docs I can tell there are times that my BP is high. I'd get a mild headache with a slight feeling of pressure in my head. This usually happens when I'm under a lot of stress.