Low blood pressure when resting

Hello, I got diagnosed last week and I really need to know if anyone suffers from this.
Basically when I’m at rest I.e sat down on sofa or driving my truck, my blood pressure goes down low. 100/51 is an example but sometimes it’s even lower than that. And then when I stand up I get dizzy, and when I’m driving I feel very sluggish and fatigued, after only ten mins of driving, BUT once I’m up and about and moving my blood pressure goes back up and I start feeling better, is this my Ms? I have blood pressure tablets that I have not taken yet, as I just wanna be sure it is neurological. I’m getting to the point now where I’m gonna quit my job and stop driving. My fatigue after just driving for ten mins is awful. I feel completely wiped out .