I would definitely increase water intake, to start to change the chemistry first and foremost; it's healthier anyway. The other thing is that it can be difficult to rule out ammonia smell coming from the urethra or vaginally.

If it were me and all the other things vaginally were coming up negative (for infections), if it hasn't already been done, I would checked out by getting blood work and a complete urinalysis done, to see what might be going on instead of guessing.

It's frustrating, no doubt (! ) but ask to have the lab work done as there might be something that you can do more than playing a guessing game, especially if you are going in anyway. It can be an indication of something that can be easily taken care of with the right information, could be diet and/or could be something just as simple. Good to have the right information.