Wow, this is a tough one. I hate to see a mom and baby who love breastfeeding not be able to continue. You really have two issues going on here, your medication need and possible allergies.
For the medication, I agree it's better to avoid nursing while on provigil since so little is known about its safety. But if one of the other options would work for your narcolepsy, you should be able to continue nursing. I just looked in Dr. Hale's forum, and it appears that Ritalin is the safest of your medication options. Here's his response to a question about adderall:
Adderal is just dextroamphetamine. On page 205 of my book, I have a complete rundown on this drug.
for an alternative, I'd suggest Ritalin. While we don't have any
published data, we've studied milk levels in several women and they are
modestly low. Doesn't seem to bother the infants.
Tom Hale, PH.D.
I don't have his book (Medications and Mother's Milk), but most LLL leaders and lactation consultants should have it if you would like to read more about these drugs.
As for the allergy issue, do you know what allergies your son has (and your baby is likely to have)? Babies really cannot be allergic to breastmilk, but they can react to proteins that pass into the milk from foods the mother eats. If you avoid eating the allergens, she should not react to your milk. Dairy is the most common one. There are a couple of ways to approach this if you want to try to eliminate her allergic reaction. You could eliminate one allergen at a time to see if it helps, or you could go on an elimination diet and eliminate all potential allergens at once and then gradually reintroduce them. There may be some dietary sacrifices involved, but if you can eliminate the allergens, your milk is still the best thing for your baby and can potentially protect her from food allergies down the road. I'm sending you a PM about an article I wrote about allergies and breastfeeding.
I hope you can find an answer that works well for you. I'm sorry you are facing so many challenges to breastfeeding right now.