What can cause an Ongoing Kidney Infections and Pain?

Hi there, I am new to this forum but i just wanted to share my experience and see if anyone has experienced the same thing or similar because it has been going on for ages for me. 

It all started about 4 years ago when I started getting recurring UTIs. I was put on Nitrofurantoin every time and told to drink lots of water. However in December 2016 I was rushed to hospital with a kidney infection that had developed into sepsis. Luckily my mum was allowed to stay with me because I was 17 at the time. I don't remember a lot of that experience apart from being in agony. 

After that, my kidneys have never been the same. I started to get infection after infection with the most horrendous flank pain. Both kidneys seemed to be affected and if it was my right kidney in the most pain for one infection it would be my left kidney for another. I was put on Ciprofloxacin every time and the pain would improve when I was on the antibiotics but come back almost immediately after the dose finished. I couldn't take Nitrofurantoin for a simple UTI anymore because it would develop straight into a kidney infection so I was always given Cipro. 

When it was at its worst, I was getting a kidney infection every month. I was finding it so hard to function with the pain, constant need to go to the loo, fatigue, nausea, etc. Then I could no longer take Cipro as it started to lose its effect and I would still be tested positive for blood and infection in my urine immediately after the course stopped, so I was put on Coamoxyclav. My infections would get so bad that I would have to go on 3 weeks of different antibiotics just to get rid of one. 

I was being constantly referred to A&E by my GP because of the pain and vomiting but then A&E would send me home with more antibiotics and the cycle would continue. I was referred to Urology and tested for kidney stones which came back negative and blood tests said kidney function was all normal, so it was suggested that my infections were just one of those things because I am a girl and I was told that I would grow out of it.

After about two years of relentless infections and hospital trips, I was fortunate enough to be taken to see a private urologist by my Mum. He continued to prescribe me antibiotics for my infections which were getting so bad but he also wanted to look into the cause a bit more. Anyway after many scans he suggested that my kidneys seemed to be functioning well but they were slightly larger than normal but he said he couldn't see anything else. So he then suggested that my problem might actually be lower down in my urinary tract, so I was sent for an ultrasound of my bladder which confirmed that I was not emptying my bladder out fully. After this a cystoscopy showed that I have a urethral stricture, and so the doctor had to dilate my urethra to perform the cystoscopy because it was so restricted. The doctor at the time told me that this was most definitely why I wasn't emptying my bladder and he said that the dilation should hopefully help. Well, the dilation did not help and I went back to having to push my urine out again by that same evening. 

After my follow up appointment with the private urologist where I thought he would discuss with me treatment options for my stricture (I should  mention here that I go to the toilet SO many times throughout the day and night and I constantly feel like my bladder is full) he told me that I would need to go on antibiotics for the rest of my life and that is all he could do for me. So I was put on a low level of Nitro for three months, however I had a really bad reaction to it where I would throw up all night long after taking it that evening and, consequently my kidney infections did not stop. My mum and I worked out that at one point during my second year of university I had been on several antibiotics non stop for a total of 65 days just for one infection. I was feeling the repercussions of these antibiotics in many other ways including persistent thrush which just didn't seem to leave me alone. Anyway, I then saw the private urologist again who said that the plan going forward would be to still be on antibiotics for the rest of my life but to change the antibiotic every three weeks by going to see him.

Needless to say, I do not want to go on antibiotics for the rest of my life as I am only 21 and myself and my parents cannot afford to see this doctor and pay for a prescription every three weeks indefinitely. 

So I now feel very stuck. I am still getting kidney infections, though I have discovered D Mannose which is helping slightly to reduce the number of infections I get, though not completely and the pain is always there. I still have a urethral stricture and the constant need to go to the loo and a feeling that I cannot empty properly. I have a constant pain in my flank on both sides and it is all getting to me massively and I don't know where to go from here. I have noticed that the pain in my flank gets worse when I need to go to the loo, particularly every morning when I wake up bursting to go (even after having been two or three times in the night).

I did go back to the NHS after my last appointment with the private urologist and the doctor I saw seemed reluctant to suggest anything contrary to the urologist.

Has anyone else have a similar experience? I would be so grateful for any suggestions or advice! I'm worried that with all these infections my kidneys are going to be damaged and I don't know where to go or what to do about it.

Thank you!