I know how you feel, slightly . About a month ago I had a really....really bad ear infection. Just previous to that I had had to go to the doctors twice in a week over 2 other medical conditions. I was in absolute agony with this ear infection, and when I finally got in at the doctors, the doctor commented how ooo.. only just seen you..she gave me Amoxicillin.. despite me telling her I'd just had it for a wisdom tooth infection and it hadn't had any effect. So she still gave me it and it had no effect whatsoever. In the next week I had lost my hearing, I couldn't move because I went dizzy whenever I stood up and threw up because I was in so much pain. I went back a dose before I was due to, and they gave me doxycycline, and strong cocodamol. Both of them I had an allergic reaction to, I couldn't breathe properly, it felt like someone was stabbing me under the ribs, I rang NHS direct and they were like ''just lay down''... my asthma inhaler did nothing. I went over to the pharmacy and just started crying because I was in so much pain and was too afraid to go to the doctors again because I was made to feel like I was going too much when really everything was coming at once. I was finally persuaded by the pharmacist to go back to the doctor and in the end I got a really nice one. She put on the system that I was allergic to those antibiotics, along with three other ones that I had repeatedly told the GP i was allergic to yet wouldn't listen to me. She gave me a different antibiotic, and lots of useful tips. I was fine after a week, and got my hearing back after 3.
So I know how you feel about how GP's think your losing the plot for coming so much, but at the end of the day, its our health, not theirs, and we have to take care of it and its their duty to help us, so keep going back, every single day until you get the help you need.