Flue and water infection

You can get sachets of powder (to mix with water), containing sodium citrate or potassium citrate. If your symptoms don’t clear within a few days you should speak to your doctor or the pharmacist as you risk damage to your kidneys. Drink plenty of plain water and take paracetamol or ibuprofen for the pain.
Hope you feel better soon.

You say you don’t want antibiotics but you may well need them I m afraid
I ve had many water infections over the years but never been able to get rid of them with self help once they are established I ve occasionally stopped one from starting with regular bicarbonate of soda drinks ( horrible) to neutralise the acidity but not once it’s took hold
I would go to your doctor and get proper treatment before it travels to your kidneys