Kick Me While I Am Down

Travis took my car in for service today, so I was basically stuck at home with three kids under 4 and a Porsche Boxster. Travis had dinner with some friends from his old job so I put the kids in the stroller and headed over to Trisha's for dinner. On our way over Jack was talking a mile a minute:
Jack: Look at the doggies, mom
Me: I see them
Jack: I think that man is angry with them
The man was walking a Bassett Hound and a Black Lab; the Bassett Hound kept running into the bushes and twisting the leash around them. When we were walking past the man I said, "Those dogs look like they are more trouble than kids". The man took one look at me and the three kids in the triple stroller with the open bottle of wine in the pocket and said "I bet it would go better if I carried a bottle of wine!" For the record, I hadn't even had a sip of wine, it was to have at Trisha's.
Jack: What are those black lines?
Me: Tar
Jack: What is that for?
Me: They are expansion joints for the woad
Jack: Mom, the word is Road, can you say rrrroad?
Lauren: Road!
Jack: See mom, even Lauren can say Road, can you say rrrroad?
Me: Yes, Jack I can say road.
Jack: Then why didn't you say it the first time?
Kick me while I am down Jack! Lately, when I am exercising I end up slurring my words when I get a little fatigued. I don't really know how to explain MS to Jack. I have told him that I have MS and he knows that I have to have a shot everyday, but he doesn't know anything about the symptoms. I don't want him to be scared, but I do want to teach him to be understanding of people who are different than him.