My 14-year-old daughter got her first period a few months back and had it for a month. Yesterday she went to the bathroom and saw some blood when she wiped her vagina. But she had no stains on the pantyliner that she had worn for 2 hours that day. She thought her period was starting again, so she put a pad on. But until today, she has not menstruated, not even a little bit, or had vaginal discharge or spotting. Why is this happening?