You don't say if this lower BP is your normal or if this is just recently. If it's recently you should make an appt tomorrow with your doctor for an evaluation to determine what the cause is.
Here is some other information on low BP.
Low blood pressure is an abnormal condition where a person's blood pressure (the pressure of the blood against the walls of the blood vessels during and after each beat of the heart) is much lower than usual, which can cause symptoms such as dizziness or lightheadedness.
When the blood pressure is too low, there is inadequate blood flow to the heart, brain, and other vital organs.
A blood pressure level that is borderline low for one person may be normal for another. The most important factor is how the blood pressure changes from the normal condition. Most normal blood pressures fall in the range of 90/60 mm Hg to 130/80 mm Hg, but a significant change, even as little as 20 mm Hg, can cause problems for some people.
You can read more here too
So do make that appt. If you feel anything else tonight such as, chest pain, shortness of breath, irregular heartbeat, fever or headache, or anything that just doesn't seem right, then by all means do go to the ER tonight.
Good luck, If you need anything else please feel free to ask. If you found this helpful don’t forget to click the *accept* button!