I'm glad you're feeling better. I too have battled with kidney infections and stones. Regarding the stones I have to say you will know, without a doubt, when it's a stone. The pain is excruciating. I couldn't even speak due to the pain. The first time the stone became stuck in my Ureter. In the valve that empties to my bladder. I had that thing for seven horrid weeks! The pain from kidney infections can also be debilitating. But if it's a stone you wouldn't be walk around or go to work. I have been reading all kinds of new info regarding the link between Celiac disease and kidney infections/stones. They say that because your body doesn't absorb the calcium you ingest(when you eat gluten) it then gets passed on to your kidneys. So now your kidneys are filled with calcium and then the stones can form.
I have noticed that my infections occur shortly after I have accidentally consumed gluten. I am extremely careful but it's usually due to cross contamination or maltodextrin.
One last thing. You should always have your urine tests cultured. That way they can tell you exactly which antibiotic will work for the specific kind of infection that you have. They can be different every time or the same every time. The culture may cost a little more initially but it will save you a lot of time, pain, and useless antibiotics that over time your body can build up an immunity to. Hope this helps!