Hello good evening,
As you mentioned that you have diagnosed as UTI and treatment has started then nothing to worry if right antibiotics are ongoing, as you have not mentioned about your urine routine examination and culture report.
If you find that you are recovering from symptoms than do not mind about your light headedness because in UTI there can be high grade fever
, headache, bodyache, pain abdomen, weakness and little bit light headedness, so do not worry and keep watch on your improvement or worsening of symptoms.
But visit to your doctor as per schedule.