Low BP, Anemia, Have Uneasiness Throughout The Day, No Improvement With Changed Diet, Calcium Channel Blockers. What Is The Cause?

My mother, age 68, black female, was on beta blockers, now calcium channel blockers - but not daily. The dosage has changed often to try and regulate blood pressure. She has also taken water pills, but she experiences lightheadedness , dizziness and fatigue . Either BP is too high or drops too low. She changed her diet, but still experience low BP - 103/67. She has seen a few doctors to no avail and also a neurologist (still waiting results). She had a colonoscopy 5 months ago, and was also diagnosed anemic. She is losing hope, faith and stressed with fear. Some days she feels fine, and then others she is in the bed resting. She has had blood work 2 or more times with low iron, then Vitamin D deficient, etc., but still she experiences BP too low. What could be happening? She lives in a small rural town in Alabama with very limited actvity.