High PH and Crystals in Urine..Help!

My almost 3 year old Yorkie started having bladder problems almost 2 months ago. I first noticed because she peed in a few spots in the house. She doesn't have accidents unless she is sick. I took her to the vet and she had a bladder infection and high alkaline urine. It was a 7.5 at that point. They did an xray and ultrasound on her bladder- no stones or crystals. They sent me home with 3 weeks worth of antibiotics. A few days after she was done taking them, I took her back because she had another accident. At that point they recommended we send a sample of her urine off for culture because the infection was still there. They also had her start Hill's Prescription (dry) C/D and said it would lower her PH level. She started on a second antibiotic and eating only the prescription dry food. After 12 days, we went back again (because of more accidents and she was looking miserable). This time (3rd visit) the infection was gone but the PH balance was 8.0 (even though for 12 days she had only eaten the prescription dog food that was given to lower her PH balance). I asked the vet about it being even higher after eating the food and she said it could take a month to work. That didn't make much sense to me because it wasn't even stabilizing it...it was higher!! She also now had crystals in her urine (these were new). That third visit we left with a second prescription food (Hill's S/D that they said would dissolve the crystals) and a anti-inflammatory meds because "maybe" her bladder is inflamed and irritated. Now, for 2 weeks she has been eating BOTH prescription dog foods and taking a single dose of the anti-inflammatory medicine every day. Three days ago she peed on my bed again and in a few other spots. I started giving her cranberry pills and distilled water recently too to try and help. Yesterday, she threw up and had about 4 accidents that I saw. (when I say accidents, I mean only pee spots). Last night I put a little chicken broth in her water to make her drink a larger amount. I may keep doing that once a day. She has always seemed to drink enough water but maybe it's not enough.

Obviously the food is not working as it seems like she is just getting worse. I am miserable with her. I can't stand the thought of knowing she is in pain. I don't know what else to do! I am frustrated at the vet and at a loss of what to do next.