Glad you and Brooklyn got through the day OK! The dose of gabapentin she's on is the basic starting dose recommended by Clare Rusbridge. If her problem is neurological, the gabapentin should make some difference to her pain level/episodes quite quickly, even if that small dose doesn't deal with it entirely - as has often been said on this forum, finding the right meds and the right dose is often a case of trial and error for a few weeks. Great that your neurologist is so clued up about SM, and especially that she's working with the Griffon people, some of whom are getting good results by sticking to the breeding protocol. I know a month seems a long time to wait, but if it gives you time to sort out insurance, you'll be able to take Brooklyn for her MRI with some major worries dealt with.
When you've caught up on sleep, take Brooklyn for your favourite walk and just enjoy her!
Kate, Oliver and Aled