Mom,
The symptoms that you describe (heart rate and dizziness, nausea) are more connected to decreased BP/decreased ability for the body to correctly regulate changes when you move as opposed to high blood pressure. High pressures would show up as more of a pounding headache; otherwise hypertension is called a "silent killer" as there really aren't signs that you see before there is damage to the end organs. For you to have symptoms from a high pressure, it would have to be really high (like "having a stroke" high). The medications you describe are much more likely to give you something called a "orthostatic hypotension" or "postural hypotension." You may ask you MD to do something called orthostatic blood pressures on you when you have symptoms or if you can induce symptoms (stand up really fast, turn your head fast, etc) to check for this.
Hope this helps,
Lori Lee