I am so sorry the migraine will not go away. It produces that feeling of absolute despair, and I'm so sorry about that. Did it get any better with the prednisone? When are you going back to the neurologist?
Did your neurologist talk to you about any other factors that could be triggering you and/or making the attack worse if it is indeed migraine? When I was in my first status migrainosis I discovered I could make it temporarily better with the lights off and screens away (this is how we figured out I was horribly light sensitive.) Some people are sound sensitive. There are foods that are common migraine triggers that I was eating at every meal and triggering myself over and over again. For migraine, often being in a dark, quiet room helps make pain somewhat better. Being able to sleep is important since sometimes sleep can lessen a migraine. Have you tried some mild exercise like walking to help get you sleepier when it's bedtime?
If it's hyPOtension (too low) that's where you have a leak somewhere and your brain doesn't have enough pressure swimming up there. In that case, the headache should be lessened by lying flat (like on one thin pillow) and drinking LOTS of water.
My friend with hyPERtension says it helps to be more upright like in a recliner instead of flat.
Obviously you don't want to have any of these problems (no one does.) Both ICP conditions can be comorbid with migraine. I have found my hyPOtension pisses off my migraine brain and that me sleeping super flat and taking breaks in the day to lie flat reduces my number of bad migraines.
One thing you might try while you're waiting to go back to the doc is looking at what you're eating and seeing how it matches up to what is migraine safe. If I look at this list: https://migraine.com/wp-content/uploads/2015/02/elimination_diet_comprehensive.pdf
...which is very comprehensive, I can eat most of the "safe" stuff on the left, and even some of the no-no stuff on the right doesn't trigger me. MSG is the worst trigger for me, and it's hard to avoid. https://migraine.com/blog/locate-hidden-msg-migraine-triggers/