bp fluctuating

I'm a 62 year old male...excellent health...avid runner - 40 miles a week...6'3", 180....cholestoral 164 - hdl 66, ldl 83. Take Diovan 160. My bp fluctuates dramatically....have intense "white coat apprehension." Sometimes 162/90 at Drs. office....drops to almost 140/80 after a few minutes of relaxing....in evenings at home, usually around 118/62 or something like that....can I assume the diovan is working even though it gets high sometime?