What Causes Appetite Loss And Headaches While Having UTI?

Hi, since last Saturday I have been suffering with appetite loss, severe pain in both sides and severe severe headaches to the point I can t concentrate. I went to my doctor and he said I had a Uti (confirmed via dip test) he put me on antibiotics however I did not feel better in anyway shape or form. I ve been back today and all he has done is put me on a longer set of anantibiotics. However I know that these severe headaches I m getting are not related to a UTI, what else could it be?