It is important to take the Advil within 30 minutes of onset of symptoms or it will not work.
A migraine can present like that. I get migraines if I accidentally eat nuts or gluten. Mostly just the light show migraine aura for me now, but my niece just had an incident like you are describing, and the doc said it was a migraine. Watch your diet for other food allergies like nuts, dairy, soy. Take a gluten-free ibuprofen. Advil is fine. CVS has one they say is dye-free, and it is also gluten free. Cosco has Kirkland brand that is GF, but another brand I got was not GF per other Celiacs on line.
That sounds brutal and frightening. Glad you are in a doctors care. I assume you are having or had a brain MRI.
There is a MS community here at MedHelp. Some members there may be able to guide you.