UTI antibiotics don’t seem to be working

Need some advice. On Friday I called my doctors as I felt like I had a UTI. Had symptoms since Wednesday. They checked and I tested positive for UTI, put me on antibiotics straight away. Fast forward to today, I am still having all the symptoms, feeling worse than on Friday and just eh. Called doctors today, said they don’t have time for me, to call tomorrow and hope that they have an appointment free. I have no idea what to do, I’m a little worried that it may be a kidney infection, but they haven’t advised me anything and I also don’t want to waste the hospitals time. Any advice?