Period after Birth control

I went off BC last month (last pill was August 30th) to try and conceive Baby number 2. I got my period sept 1 for 4 days and since then no period has shown up but I also have no pregnancy symptoms. I was completely regular on periods about 28 day cycles before birth control. Any ideas why as I am on cycle day 33... do you think it's because of being on the pill? Do not think I am pregnant. Thank you