What Causes Low Blood Pressure, Weakness, Nausea And Headache?

Question : I have labile HTN, episodes of very low BP as low as 70/47, 80/56 that cause weakness, nausea and headaches, in the same day i can go as high as 168/144 or more commonly 150/100, 147/100. I get these high readings if feels like my heads going to blow off. The very high readings are more normal for me. The very low readings are new in the last month. My doc has since taken me off of cardizem and diovan but kept coreg because of resting tachycardia. I have had high and labile BP (with no hypotension) for 10-15 years. My BP has always been difficult to control, but it has never caused symptoms like this. I have a recent history of spinal cord compression, it has been a year exactly that I had C3 laminectomy. I had compression for at least 2 years, maybe longer. Prior to that, the original injury was C3-C5 disk herniation, spinal cord injury and compression. I was born with a small spinal canal and disk herniation inward left no room and therefore compression. I have struggled with spasticity, muscle weakness, incoordination, poor balance for 15 years. Since about March I have almost no spasticity, no balance problems and can run for the first time in 15 years. My question is could this recovery have caused my BP to drop and could I be getting better instead of developing some new problem or disease?