I know how you feel!
Almost everytime I go into the ANC and have my BP taken, Its always on the high side. Then its taken again within minutes and its perfectly fine.
I am a bigger girl too, so I now request that they use a bigger cuff, adn I try and breathe nice and slowly as they are taking my BP. the larger cuff doesnt hurt as much, and by me concentrating on my breathing, I don't think too much about the BP. It has been really good the last few times I have been in. The best readings I have had, even better than before I was preggers!

Try not to think about the cuff and what the doc are doing at the time. I really find concentrating on my breathing helps me heaps!

Hope you fidn something that works for you. I'm sure your docs see it regularly anyway

hugs
Nicky