I had a migraine so badly a month ago that I had to shout (which was agony) for someone to go and find my Triptans at 3 am so I could take them, to take the edge off enough to go back to sleep. I've had to go to Out of Hours before with them after 3 days and no respite.
You feel unbelievably sick, and heavy, and you have physical pain crawling round one side of your skull so severe that just resting it on a pillow hurts. You also have a throbbing ache in that area, and pain so intense in your head it feels like someone with huge boots is trying to kick their way out. You can't open your eyes because light hurts and there are bright flashes in them unless shut, and you are dizzy to go with the sickness. You also have this weird sense that you are moving through water - a shaky water that disconnects you from the world. That part usually starts before the rest, and it's called an 'aura'. That's when you need to be somewhere near the meds to have the least hope of preventing the rest in full flood, lasting days.
It's almost impossible to visit the loo to piss when you have a fullblown migraine. It's non-functional. I'm lucky and don't get them that often, but when I do? Well, I had chemo on Friday, and it's a bloody doddle coping with these side effects in comparison. The meds are really effective at quelling the nausea and vomiting, for a start.
YABU, and I admire you for recognising that. But I did want to try to explain exactly how terrible they are, so you recognise what she has to live with.
It's lovely that you want to help, but unless she's not very bright she will have looked all this stuff up. It's so variable - sleep deprivation and hormones are connected to mine, and once I am nearing one food is then really significant. Exercise makes no odds, though. She will have had help and support on this stuff with her clinicians, I expect? The best way to help is asking how supportive she's finding her doctor, and has she been referred to a specialist to see if more can be done? Listen and support, don't try to fix, essentially. With any serious medical condition (you wouldn't believe how many genuinely lovely people have tried to convince me to skip chemo in favour of a special diet - well meant, but so annoying, truth be told. She's the expert so ask and listen - as with most things, that's one of the best and kindest things a friend can do.)
Again, I do understand that you just didn't know, and it's actually great of you to ask, listen, and take this all on board. You actually sound like a lovely person who just had no idea.