Why Are Medicines Not Controlling My High BP ?

im a woman of age 55, height 5 feet, weight 75 kg, suffering from High Blood pressure for more than 7 years (Bp averaging 150/ 84). But recently(2 yrs) my bp average is 165/89. For last few weeks, on an average 3 days of a week, my bp turns to 190/ 100. Sometimes vomiting occurs. My doctor prescribed medicine a few years ago. and i am still taking those. But why those medicines are not working to control my bp? if you ask me about those medicines i may tell you.