Hello and congrats on your pregnancy!
First, let me tell you that you are not alone and loads of women with MS have children without anything being more problematic than it already is in itself :)
The very good news is that during the pg, it seems our autoimmune system is on standby so it generally is a great time to do loads.
That's what I'm currently experiencing at 35 weeks: great mood, loads of energy, some of my long lasting symptoms even have regressed (bladder control, yeah!). I am not usually medicated though (I have a non aggressive mild form of MS) so I didn't have to change anything to my routine.
I was warned that I could relapse within 3 months of the birth of my DS but, again as I'm not usually on meds, I've adopted the wait and see attitude and I plan on bf for as long as I can. If symptoms do appear and I need to be admited for corticoids, this is my plan:
med info related to my type of MS and my evaluation of risks, please check with your neuro for your specific case
My neuro said bf and Solumedrol (methylprednisolone) is fine if 50mg/day, to wait 4 hours after the end of the drip to bf.
So for the 5 or so days I'll need much higher doses (around 1g/day usually), I'll use stored bmilk and a specific bottle that reduces nipple confusion, and as soon as my doses are lowered (I'm usually at about 50mg within 10 days) I'll bf again.
I've bought a greensheep co-sleeper and plan on renting a good electrical double breast pump. If I'm exhausted after the main part of the treatment, I'll ask for help with the baby, my friends and family are all aware it might happen. If all fails, well, let's say I would have tried my very best in these not so easy circumstances so I'll give myself a break and go have a pedicure to cheer me up.
I'd recommend you get in touch with a MS patient support group as you're very likely to meet fellow mums who will have loads of tips on how to manage bf, fatigue and potentially reduced coordination. Also, remeber that MS is not a tragic illness, many people live with it with minimal issues, having kids is great :)