My dr believes that im 27 weeks pregnant based on my last period of July 26th. Although that was my second "period" that month. I am usualy regular, my period always came around the 10th of the month and last July i got one period July 9th and then again on the 26th. My period on the 9th lasted the usual 4 days. On the 26th it was 2 days and ALOT lighter than normal. I also have twins that run in my family so maybe the second period was a second egg that didnt get fertilized? Any body have any thoughts?