Hi there I understand your concern and anxiety...unprotected sexual act might have caused some abrasion to the vaginal lining....This may also have made you prone to urinary infections or cystitis...Drink plenty of water. Water helps to dilute your urine and flush out bacteria....Avoid drinks that may irritate your bladder.... Avoid coffee, alcohol, and soft drinks containing citrus juices or caffeine until your infection has cleared. They can irritate your bladder and tend to aggravate your frequent or urgent need to urinate....consult nearest gynecologists they will do the needful.

It is most commonly urinary tract infection. Do urine routine and culture  and meet gynaecologist. Take plenty of fluids.

Kindly consult a gynac... Internal examination will explain the cause.....