Only your doctor can tell you whether you need more medication. Since you don't seem to have an adequate control of your blood pressure at the moment, some changes to your drug regimen or dosing might be necessary. How long have you been hypertensive and on medication? Have there been any changes to your lifestyle or circumstances recently? Stressful situations, anxiety (fluctuating hormone levels) and many other triggers can cause dramatic transient blood pressure spikes. Even a fatty or salty fast food meal can send one's blood pressure soaring. Certain hormonal disorders and medical conditions can have the same effect on blood pressure. You'll have to work with your doctor to determine the cause of your blood pressure spikes. As a rule, people are advised not to double up their medication doses unless directed to do so by their physicians. All drugs are therapeutic (in most people) when used properly but also toxic when a certain point has been reached. That is why the maximum recommended daily doses are rarely exceeded.
Good luck! I hope you'll get to the bottom of this.