Following is only my own experience hope it will help you.
After life time of suffering I have came to the conclusion that it is my brain inflammation causing the headache. I can feel the brain swelling inside the skull.
Once the symptom comes, it won’t stop on its own only getting worse, blur vision follows. The pain and dizziness is constant, any slight movement will trigger vomiting.
The only way to calm the pain and make it disappear is to relieve the inflammation, fight it right from where the problem started.
My battling is simply take aspirin because it has anti-inflammatory effect (or painkiller with aspirin ingredient not paracetamol), the type that you dissolve in water first is more effective; I take “Aspro Clear”. I can feel the brain slowly deflating and the pain calming down.
The most severe occasion I can remember was taking 4 doses (2 tablets each), that was because I determined to fight the pain without taking medicine, but the more you leave it, the longer time it would take for the pain to disappear.
However, please do some research first to see if you are safe to take aspirin for example, cautious should be taken if you have stomach ulcer. And also because you have been taking so many medication.
Good luck. All the best.