Probably the reason your doc's seem unconcerned is your not passing out!
However your bp would be considered low ie Hypotension
You really need to get blood work done to check for signs of infection and a Bp reading cortisol check. That's where they take your BP and draw the sample for cortisol level at the same time.
If that check's ok then a echocardiogram to check for ejection fraction to make sure the muscle is doing it's job.
The blood test I believe will reveal the problem however you also didn't mention how long this has been going on?
As far as the heart running a little faster is it's trying to keep the bp up by adding more volumne it does this by speeding up. On the other side a person with high blood pressure usually has a slow heart rate. Teeter-tauter effect it's normal.
The C effect tends me to think infection. Get it checked out! Till then keep up with the V-C.
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