Its a bit of a catch 22, as you need to eat in order to speed up the process of the medication and also prevent irritation to your stomach, but if you are nauseous and not eating then taking the tablets will be upsetting you, and making you feel sick. I have never had a problem with Trimethoprim either and sympathise with you. In order to reduce your pyrexia you def need to take the Paracetamol , or , ibroprofen but if you cant stomach the Paracetamol cant see how you could manage anything else. Seven days is quite long to be on a course of antibiotics, its usually three days now , though the jury is out as to whether or not thats long enough , so if you have had seven days,even at a reduced dosage , then that should be adequate to deal with the infection. If you can, hold off until Monday and you can discuss it more fully with your own GP but try and eat enough to be able to take your Paracetamol meantime .