UTI negative or ?

Hi.

I recently went to the doctor because I thought I may have had an uti.I am on my period and I even wiped before I took my pee test. They came back and said it was negative . The doctor said that they will need to send my urine out to the lab. Should I be worried? What will the lab test for ? And if my uti test was negative will it be negative with the lab test? Plz help!’