This is a thyroid forum... do you believe your blood pressure issue to be connected to a thyroid problem?
High blood pressure can strike anyone at any time, but perhaps your blood pressure was tested right after you did some strenuous or stressful activity, etc. In that case, it might not be a bad thing.
You really need to discuss the issue with your doctor, who might want to do further investigation to find out why your blood pressure is high. On the other hand, a single high blood pressure reading is not always anything to worry about - it depends on what your doctor says.