You should not determine blood pressure from one reading. Blood pressure varies over the day. To get an accurate reading of what your blood pressure is take your pressure three times a day for a week and you will know very accurately what your blood pressure is.
The best way to take your blood pressure is to have your own blood pressure monitor. They are available at stores like walgreens and wal-mart. They are also available on the web. A monitor around $35 dollars is more than adequate.
When taking your blood pressure be sure to hold your left arm so the monitor is at the same level as your heart. If you do it the same every time this will give you a more consistent reading. It only takes a minute or two to complete. Keep a good record by writing it down.
This is how the medical community looks at blood pressure.
Anything over 140/90 is considered high blood pressure. Any reading over 120/80 is said to increase risk for heart disease. This is the number most doctors do not want to exceed and they7 begin drug therapy at these levels. High blood pressure can be cured or returned to normal using nutrition and other natural means. There is much information on this site to help you keep or return your blood pressure to natural levels.