My cat has diabetes?

I was posting this question earier when I deleted it by mistake, she was first put on insulin, which didn't agree with her, had more blood work done and the vet didn't find any sugar in her blood, took her off insulin and gave me some "Glucotest"urinary glucose detection system, to put in her litter pan to see if the pellrts changed color when she peed on it, now that's been almost 1 year ago and everything is okay with her, she's also on Hill's perscription diet M/D wet, the dry was recalled so got W/D dry, she has symthoms of any diabetes. All this cost me almost $2000.00 including taking a cab with her for the many, many trips to the vet.also didn't get any refund for the insulin & syringes that I had to buy, is it possiable that she was misdiagnoed and never had or has diabetes. I pick up her food at the vet's and no one ever asks about my cat, if she's doing well or not. I'm thinking of getting a second opinion but don't want to put her throught all those painful tests again