Nini,
For starters not everyone has the same type of period, yes the average is 4 weeks but some people have a period every 5 or 6 weeks or even every 2 or 3 weeks, what I'm saying here is that there is no set time frame.
I am trying to get pregnant and went for 3 months with out having a period. My doctor ran a lot of blood tests and it turns out that I have Hypothyroidism (low levels of thyroid) and that can affect your period.
Also, did you know that you only ovulate ONCE inbetween every period, and that the egg is only alive for about 24 hours. So you can have all the unprotected sex you want but if you don't have it at the right time it dosn't do any good.
Barb
Hi!
If I am understanding you correctly, you haven't had a pregnancy test since Sept 8 and you have had unprotected sex. If you were my patient, the first thing I would do is ANOTHER pregnancy test. If that was negative, I would give you 5 days of progesterone to start your period. Then, I would recommend that you start birth control pills. They will both regulate your cycles, AND prevent pregnancy.
In the meantime, don't forget about Plan B too! The morning after pill is good for preventing pregnancy too.
Hope this helps!
Good luck!
Dr B