If a person comes to my clinic with these symptoms the most likely condition appears to be a Urinary Tract Infection. You have already received doxycycline that helps to control the infection and have rightfully avoided intercourse. However, since you have not recovered and your symptoms appear to have worsened, there are three possible explanations that may have caused this; 1. The first possibility is that the organism causing the infection does not get eradicated by doxycycline and the infection has progressed to involve the kidneys. In order to confirm this you will need to get a urine culture test to detect the bug causing the infection as well as knowing the drug that acts on the bug. This will help you in taking the correct drug. 2. The second possibility is that you may be having stones in your urinary system (kidney stones), that may be a source of infection or the stones may be moving down along the urinary tract leading to pain. To rule out this possibility an ultrasound of the kidneys is required along with the urine culture test. 3. Another reason may be an infection of the tubes and ovaries leading to pain and fever. Such cases are usually accompanied by vaginal discharge. If you are having a similar complaint than a gynec examination will help in diagnosis. The vomiting may be due to either the infection and fever or due to doxycycline that upsets the stomach. I would not worry much about it as it usually stops spontaneously once the primary condition is treated. However I would recommend that you consult your physician for further evaluation. In addition to the above measures I would recommend that you to drink plenty of water and keep yourself well hydrated once your nausea / vomiting is controlled as it helps a quick recovery by flushing out the urinary tract.