I always stop taking my birth control pill on Sunday and then get my period 4 days later (on the Thursday). I had sex on Sunday, May 29 and took plan B the next day. I did not get my period on the Thursday like I usually do and heard that it could be up to a week late. Do I start my birth control pack on Sunday June 5 as usual or do I wait until I get my period and then go back on birth control?