my gf and i had protected sex in mid june. she was due for her periods around that time. she had bleeding for 5-6 days after intercourse.since then she has missed her periods, had once blood clots, but not regular periods. we have done preg test a month after and again 2 months after. its sep mid now, but still she has no periods. she is under lot of stress due to some family reasons from last 2 months.its been long enough to even show some preg symptoms, but she has no such symptoms. please suggest some medicine for her periods at earliest or what could be the reasons for missed periods.