I'm 19. My last period was August 20th. I last had sex at the end of July. It was a little different than my normal period, lighter and not as long. No cramps or anything. Now my period was due about 3-4 weeks ago and I still haven't gotten it. I will say I have been quite depressed the last few weeks and even more so this week after the very tragic loss of a close friend/ex. Is it just from the stress/depression? Could I be pregnant even after having a period in August? I really have no signs beside mood swings and occasional cramps. Should you see a doctor for a late period? Or wait longer?