Should I be worried?

Last year I started getting repeated UTI's, I had about one a month from June to October. I had an ultrasound and found out that my left kidney was half the size of an normal adult kidney. From then I was put on a long low dose to help reduce the risk of more infections. I had a Cystoscopy to check that there was no problem with my bladder and there was nothing wrong there, however my specialist said that my urethra was small and that could have been causing my UTI's, but the procedure had stretched it and so I should be ok now. I was unhappy with this response as it didn't explain as to why I was suddenly getting uti's out of the blue. I asked if there was anything else that I could have done. I then had a renogram and found that my left kidney was only functioning at 15%. But still my specialist wasn't being very helpful, he said that after being on 3 months of low dose it must have cleared any traces of infection up and I should be fine now. So I came off the low dose and low and behold I had another infection. I had to practically beg my specialist to let me have a CT scan to try and see what more is going on, I am waiting on the results of this. All my blood work and urine tests are coming back fine.

Recently my left kidney has started hurting more often, and if I do anything slightly strenuous, for example I went for a day out in London, my left side swells up, even pushing my ribs up, it doesn't really really hurt, even when I press on the area, it just feels uncomfortable. The swelling goes down when I rest. I have an appointment on July 7th, should I be ok waiting until then or should I seek medical attention sooner? Thanks for the help!