Bonnie, I have severe whit coat syndrome too, and my doctor's office readings are usually sky high. Years back my then doctor had me wear a holter monitor for 24 hours, and said "you're right about the white coat thing. When you where here your pressure was sky high, 20 minutes after you left it was much lower, 40 minutes later it was normal, and then remained normal the next 24 hours" (despite stresses at work, etc). Then it began to rise again next day as I headed back to the doctor, and was sky high at her office again!
I do check it at home fairly often, and do drink a daily cup of hibiscus tea which helps a lot. I just started with a new doctor last week, and that day my BP was 114/78 at 8 am, and at 1:30 pm, just before I left for my appt, it was 170/105!
At the new doctor's office though they used a very large cuff and got a reading of 156/90 which is probably a lifetime low at a doctor's office.
I also highly recommend Dr. Welch's book Overdiagnosed. I was already aware of much that was in it, but also much that was really high opening.
I've always been the sort who avoids doctor's as much as possible unless I really feel weirdly awful (not just "normally" awful like having a dreadful cold), and I've had many people tell me that it's going to kill me. After reading the book I'm not so sure.