I don't have any idea of this important answer but you need to ask your doctor. Though I certainly have been through this before many times so I understand your concern. Mine is always high and I take two different BP meds ; often, I have been in situations with other problems (not related to BP) and found out when they did vitals my BP gets around 200/100 when I am in pain and/or distress.
like last time, a month ago . I was going through a severe dizzyness and vertigo and called ambulance ( I was anemic for another reason but had been told to go to ER for the anemia/dizzy thing)
some paramedics scare the crap out of me telling me I could die from the BP causing a stroke or heart attack but after waiting in ER for many hours with nobody acting like it mattered, it leaves me confused.
I get those headaches, too. That most likely IS from the high BP. That is what I am always told.
You need to tell your doctor and specifically ask him or her how do you know what constitutes an emergency for this, and absolutely, what should you be doing differently to get a handle on the BP.
And females are not treated the same when being evaluated for stroke/heart attack risks. So if you feel that is true for you, insist they check everything. I have heard about too many women being told their heart is fine and then they have a heart attack. My neighbor was told to go home and come back in the afternoon, for an appointment then, when she presented at a medical clinic and she was short of breath, with chest pain and I forget what else.....( she was also a smoker , bad diet, family history of heart disease ) She did as she was told, went home to wait and died on the couch.
That is when I finally started taking my HBP seriously. Hers, by the way was not even close to being as high as mine. It was something like
169/90. And she even had the bad chest pain, but usually women do not have those symptoms as often as men. We usually have vague sx, like nausea, dizzy. etc.

And one more thing, I just looked at the pop out profile info of yours. I want to say since you do have history of depression and all that, do not let them ignore your concerns which might happen if they think you are just being anxious because of your other history. I recommend, if you have not already done this, to also look into things such as yoga and mindfulness. So you can learn to reel in the reactions your body has ( that feels like it is not under our control but is ) such as rate of breathing etc, which will lower the stress hormones from coursing through your body. Because that aspect of anxiety will affect blood pressure and breathing. It may be harder with asthma but hopefully helpful anyway. Good luck

Hello, I hope your thanksgiving was good. To answer your question when to go to the E.R. When My blood pressure is up there and you have a really bad headache i would go because you don't know if you are reaching that STROKE ZONE. It is better to be safe than sorry.