So it was a bladder infection. I'm sorry your are having to deal with that but a day or two on the abx and you should be feeling better. Not 100% but better.

As Snoopy said, you may be retaining and that definitely can cause bladder infections. I'm a retainer too. The retention was not bad enough to warrant medication, although it was offered to me. I opted not to as I was not getting infections and such. I now take my time when going and don't ignore it when I just went and need to go again. It may be helpful to you to see a urologist. They can do some testing to find out how your bladder is functioning. A lot of MSers have a urologist as part of our team.

I hope you are feeling better.