With a truly sudden elevation, I would be looking for something else in my life that changed around the same time or right before my blood pressure went up. If you are female,
estrogen replacement therapy can make your blood pressure go up; estrogen acts like a salt. Which brings us to dietary changes, are you suddenly getting a lot more salt in your diet. Also, some herbs, like licorice, can trigger a rise in blood pressure. Stress, anxiety, or physical pain can do the same thing.