Surgery date July 11th....

I have my date scheduled, but I am getting a little scared... This is going to be a big change! My problem is that my BP has been going up and I am retaining fluid and my doctor has been known to reschedule surgery for gaining 1 pound and as of 2 days ago I have gained 3... Went to my doctor and they said it is retaining water and gave me another fluid pill.... I don't want to reschedule. Any advice?