I completely agree with everyone here. I don't participate often here, but your story sounded SO familiar... Right down to the city... I had to jump in.
In 2002, I, too, was admitted to the hospital after going to the ER for strange symptoms (legs going numb and tingly from knees down). I was released after a few days, told my MRI was suspicious, but the attending neurologist didn't want to do an LP and told me to follow up with the MS clinic in a few weeks. MY GP referred me to his neurologist of choice (also by one Chicago's top MS doctors), he was very eager to diagnose and start treatment based on only 1 attack and a suspicious MRI (3 lesions instead of the 1 you've got), but he felt that he needed another supporting clinical sign so he ordered LP and evoked potentials... sure enough, my LP came back with all the telltale MS elevations in proteins, bands, etc. If it had come back clean, I'm sure he would have held off on the diagnose and treatment. Instead, I got a diagnose and started treatment (at his urging but completely my choice).
Incidentally, I've since moved to another part of the country and have had two different neurologists agree that my neuro. in Chicago was absolutely correct. I've also had a second attack, so for me, the other shoe did drop and I accept that I've really got this thing.
I highly recommend getting a second opinion... I'll be happy to share my Chicago Doctor's name with you if that's appropriate here. Don't know all the rules.
Good luck to you.