Symptoms of low blood pressure, medically known as hypotension, relate to decreased blood flow to many areas of the body. Symptoms can include fainting (syncope), dizziness, or a feeling of lightheadedness. Decreased blood flow to the coronary arteries results in symptoms of angina, including chest pain. With low blood pressure, the heart rate may be elevated or irregular. Fast breathing, weakness, fatigue, cold skin, pale skin, confusion, nausea, or vomiting can occur, depending upon the reason for the low blood pressure. Other symptoms can include blurred vision and increased thirst. Shock (in which all major body organs are deprived of oxygen) occurs with severe hypotension.
Source: http://www.rxlist.com