I have burning while urinating, urinary urgency and difficulty holding my urine. I also have back pain today, but my period started on 24 Sept and I usually get back pain during periods. I had unprotected sex about a month ago and also used a vibrator that was not properly cleaned, so I am worried about UTI/vaginal infection as well as an STI. My doctor prescribed Nitrofurantoin, Amoxicillin + Clavulanate, Metronidazole, Levocetirizine and Pan 40, with Urine R/E, M/E and C/S. I need to give the urine sample tomorrow, but I am on my period. Can I give the sample during menstruation, and can blood affect the result? Should I give the sample before starting antibiotics? Also, do these urine tests rule out STIs, or do I need specific STI tests such as chlamydia/gonorrhea? Please advise whether I should start the medicines now and whether I need any additional tests.