107/57 is probably low enough to start getting a headache. It's the same effect as taking Nitro, which opens the arteries and causes a sudden drop in bp. The effects of the extra pills will eventually wear off but can take a little while. Just keep taking your medication as prescribed and it will soon be back to normal. If you start to have trouble with your speech and feel very tired, call an ambulance. I presume you have a blood pressure monitor? just check it every 30 mins for the next few hours. To reassure you, due to 480mg of bp pills being discharged from hospital with me instead of 5mg, my bp dropped to 66/51 with a pulse of 23. I could feel my heart fluttering but all the hospital did was wait for my body to remove the excess drugs. It took about 12 hours but the headaches lasted weeks. they continues to administer the normal 5mg when my bp had raised back to normal. You will be absolutely fine and have nothing to worry about. I took several of those 480mg pills to get into that state. It was as though I'd smoked 30 joints.
Low blood pressure starts at 90/60 and is not really a concern unless it gets below 50 for a diastolic reading. My BP is often around 90/60 and goes as low as 90/55. If you have exercised within the last 2 to 4 hours your blood pressure will also be low.
I am on Benicar HCT for my blood pressure and my doctor has told me to take it twice a day on occasion. If you are concerned or feeling light headed or weak you should call you doctor's after hours service to see if they have any input.
Good luck!
Jon