Low B.P.is a common problem but seen as less important than high B.P.
There are many reason why your B.P. level might be to loo.
you can easily control your B.P. to do following changes to your daily life style.
You can use more salt, as sodium can increase B.P. If you are patient of failure then consult your doctor before increasing salt in your diet.
Drinking lot of fluids you may take 10 glasses of fluid a day. during exercise
To promote blood flow have regular exercise
Avoid heavy lifting
Do not strain when you are in toilet.
Don't take prolong hot water bath.
Avoid taking alcohol.
Increase whole grains , fruits ,vegetables, lean chicken and fish in your diet.
Even then you face some problem so you can consult a specialist doctor.
If anyone has better suggestions and ideas then please let everyone know by replying to this post