I'm at a loss. anyone else?

For the past year and a half I have been diagnosed with a yeast infection, bacterial vaginosis, UTI, and vaginal dryness. My doctor has to gone back from one to the other on diagnoses. I have seen four different gynecologist within the past year and a half and neither of them can cure the itching and burning. I get it right after sex or a period. My boyfriend and I have been together for 2 years, he has been tested for STDs and does not have anything that would've passed on to me. I'll get rid of the itching and burning for a little while but it comes back. My urine is discolored and cloudy and my vagina burns whenever IP or throughout the day. I have gotten rid of my underwear, I change shampoos, I've tried lambskin condoms and I'm not sure if the lubrication we use would cause an allergic reaction but wouldn't it be over by now? I feel utterly alone. My doctor cannot give me an answer to what is wrong with me. Do you think this will ever go away? I do not have STDs and I don't know what this could be or why I can't get rid of it. I've tried every cream or prescription prescribed and neither work for a long period of time it always comes back