Hello, Thank you for your query. All this could be due to dehydration. The headaches, uti and nausea. It could also be unrelated. Would you clarify a few things for me? *do you wear glasses? *What color was your urine before the antibiotics? *do you have any other medical issues or take any medications? *any recent illness or travel? *are you on any supplements? *are your periods regular? *how are your symptoms now? I recommend : -drinking plenty of water. Avoid caffeine, sugary or carbonated drinks and alcohol, spicy food. -drink plain water, fresh juice , milk, soups. -don t wait till you get thirsty. Keep sipping through the day -Have an eye exam, if the headache persists or recurs. -if symptoms persist or worsen, see a physician to check for anemia. Hope this helps. Pls let me know if there is anything else I can help you with. Wish you good health