My girlfriend has missed her periods and it's been 25 days late and still she is not having her periods and no symptoms of periods. We had protected sex previous month. We also did pregnancy test three times all were negative one was after missing periods for 8 days and the rest of the two were done after 23 days of her missed periods. She is having lower back pain and she had a lot of white and clear vaginal discharge few days back. Please suggest what should we do?