Plan B on sugar pills?

Start your pills again exactly as you would have if you hadn't used Plan B.
You didn't need Plan B if you were on time with your pills for the 7 days before your sugar pills week.
Between all the artificial hormone in your regular birth control, & the huge dose of it you've just put into your body in the Plan B, you may find your periods don't happen for a couple of months, & you might even get irregular bleeding when you're not supposed to. It's going to take time to get your body back to normal.
You also need to do some research on how your body works. Most women ovulate half way between their period & their next period. Roughly around day 14. Your body can save the sperm for up to 7 days before that day, & keep it for when you begin to ovulate.
By the time you get to the week of your period/sugar pills, your body is no where near ovulation/fertility. Look up natural family planning. It'll show you how to monitor your body's signs to know what it's doing at any one time.
I am assuming that as your period didn't start as normal, that you had done a pregnancy test.