If you're a girl, and on the contraceptive pill, your doctor should prescribe you a different brand.
Otherwise, the general cutting down on booze, eliminating fags, using less salt, and eating fewer fatty foods should help.
As everyone has said, your doctor or nurse to did the blood pressure check should be able to give you more information, and there are always loads of leaflets about high blood pressure, in doctors surgeries, in the waiting rooms!
xxx