I had cystitis for 2 weeks and now the germs have spread into my kidney. I'm taking Keflex but I don't think it's causing any symptoms. I'm on the second day into a weeks course of the antibiotics. My fever seems to come and go and it's not as severe so fingers crossed the medication is working. I don't have diarrhoea as i've been eating too many codeine tablets and it means i'm bunged up. I did feel nauseous and dizzy but I don't think it's due to the medication. It's more the fever.