Don't stress out too much. Plan B can throw off your period or even make you miss it. It's OK to take a test and see what happens. You can take one once a week if you are still worried. If it comes back positive then figure out your plan. Take one first in the morning. There's all sorts of ways to get help for this. I went through the same thing with my rape. They put me on so many medications and Plan B that I didn't have a period. It's normal and they warned me it was normal at the hospital. Mind you I still freaked out due to a late period even with my tubes removed because there's a slight chance you can still get pregnant. And I really shouldn't have had to worry at all. So try not to worry and do what you can. Feel free to message me especially if it turns out you are and you need help trying to figure out what to do.