Check this article: http://www.knowswhy.com/why-does-urine-smell-like-ammonia/
Very good explaination.
Hey Rita,
Your question has come through to the MS community, and not the diabetic community, so ammonia smelling urine may not be something many have experienced. I'd heard of it but couldn't remember much, so I did a simple google search "diabetic urine smells of ammonia", there is a lot that comes up that you might find helpful in understanding it.
It seems that the smell of urine is a strong indicator for diabetics, the ammonia smell in a diabetic is usually due to dehydration, so yes not drinking enough can be the reason for your urine smelling like ammonia. There are other causes too, and i would hope that it wasn't just assumed to be because you have diabetes and that you have had tests to rule them out eg urinary track infection.
This lists common causes http://www.buzzle.com/articles/ammonia-smelling-urine-in-women.html
cheers..........JJ