What Causes Abdominal Pain And Nausea Post Treatment For UTI?

hi, I have a uti. I went to the doctor and i m taking antibiotics for it. I started treating it on Wednesday, I still have an upset stomach and nauseous feeling. my shoulders hurt just a little sometimes. I work at Starbucks, and I have to go back to work tomorrow. being around coffee will it make me more sick? should I still be feeling like this?