Oh Eric. Reading stuff on the internet blindly can lead you to want to poke your eyes out!

You will see miracle stories of folks that took ONE single diet, and were CURED! Then there are the sites that promote getting stung by bees! or the drink this juice, and leave your troubles behind folks! PLEASE read from reputable sources. NMSS.org is awesome, we are the folks living with this disease, and can tell you from personal experience what is or isnt working. Many of us have done extensive research.
In this group we have many very well educated folks. Some in the traditional sense, and some by the school of life. Most of us have tried this or that, or the other. Many of us have tried just about every drug out there for this MS monster, and what works great for one person, doesnt do much for another. This monster rarely affects two people in exactly the same way, even if you are identical twins! I have met twins with MS and one was in a chair, and the other was working full time in a hard job 12 hours a day, and running marathons. I have met twins that one twin has MS, and the other twin doesnt have MS!
Even if you do end up with bladder issues, there are TONS of ways to either deal with it, or medicate it, or be well hidden. This person peeing in the parking lot at Walmart sounds like they have other issues on top of MS. Walmart has FREE bathrooms to use, and they do an ok job at keeping them clean. Most every store out there has free bathrooms, and if you are having bladder trouble, you would learn where all of these spots are, and never let yourself get to the point of peeing in public.
Are they starting you on Meds? injections? pills? Have you done the MRI? the spinal tap? (many of us didnt have to get that)
Glad you stumbled in. Hope we can calm your fears.