Sorry about your earlier MC. I know how awful that can be. Congrats on getting back to TTC so quickly!
This info might help you (I'll try to make as much sense as possible!):
Short periods, light periods, and spotting can occur at your normal AF time even if you have conceived. This happens because of falling progesterone levels. When you ovulate, an egg is released from a follicle in the ovary. After the egg departs, the follicle remains active and produces progesterone for about 14 days, give or take (whatever the length of your luteal phase). If the egg does not get fertilized, the follicle dies, progesterone level falls, and you start your period. If the egg is fertilized and implants, it signals to the follicle to keep on producing progesterone to keep you from starting your period. However, in some case, the egg takes its sweet time about implanting and does not send the signal to the follicle as early as would normally occur. Not having received a full signal to keep producing progesterone, the follicle begins the process of shutting down (starting your period), yet at the same time, the egg, now implanted, sends word that you are in fact the proud owner of one fertilized egg! This causes the follicle to up the production of progesterone again, eventually stopping the spotting and getting everything ready for pregnancy. The duration and flow of your spotting/light period is determined by how late the egg actually implanted. Once signaled to stay active, the follicle will continue regulating progesterone levels until the placenta begins establishing itself and your HCG level rises.
Also: Some women are known to spot (while pregnant) around the time they would normally ovulate or menstruate, especially towards the begining of pregnancy. This is generally pretty darn harmless and not a big deal. --However--, you should definitely head to your doc, as any bleeding while pregnant should be checked out just in case.
Btw: Congrats on your
!!!!!! Sending LOTS of
your way!
Good luck, hunny!