I was stopped for a DUI, at the time I was experiencing numbness and dizziness. I suffered a stroke within 2 months of this. Could this cause this?

It might well have been a factor.  What you need to do know is to consult with an experienced DUI attorney in the area of where all of this happened.  They may be able to use your subsequent stroke as a defense to the charge,  Additionally, this is a very technical area of the law and they may be able to get the charge thrown out for some procedural error; they may at least be able to get the charge reduced.

Since a DIU triggers both a civil and criminalcase, it is always best to have legal representation.  Again, get an attorney who practices locally to where the court involved is located; they will have contacts there and can utilize them to your best advantage.

Best of luck.