I regularly have abnormally high diastolic pressure; this would do nothing for me. Then it test normal a week later, so I dont know what to do.
Hypertension is a matter of time. It’s how much time the interior of your arteries are exposed to elevated pressure and have to react to it. If you have the occasional high measurement but are mostly low you’re pretty safe.
If elderly and you’re usually low, but had enough high measurements to start treatment, that gets dangerous. During one of your naturally low period of time you could get driven too low by the meds and fall down stairs from lightheadedness. This is because nearly all treatments decrease both systolic and diastolic. Getting pushed too low even one minute of a day and that minute happened to be at the the top of some stairs and you can ruin what is remaining of your life.
Docs are very much aware of this entire thing. There is danger and letting people walk around with elevated blood pressure. There is also danger in treating people who have normal blood pressure such that it becomes low.
It sounds like you do measure away from the clinic so you have recorded numbers that are not strictly at the office. Make sure you write them down and take them with you to your appointments.