late or skipped Period after plan b?

Can I completely skip a period after taking an emergency pill (norlevo)??

So I took emergency contraception within 24-25 hrs after I had sex BEFORE OVULATION (w a condom I didn’t know whether it might’ve broken although I seriously doubt it but just to be sure I took one) and now my period is 8 days late. I took 2 tests which came out negative and I also have PCOS which can affect my cycle but I’m gonna take another test so should I be worried?? Some sites say after 2 weeks you should worry and some say after 7 days.

(I didn’t wait for the full 10 mins after the 2nd test because it said on the box within 2 mins it would show negative. It showed a negative within 2 mins and I waited 6 mins or so to see any changes, so is it possible the outcome might’ve changed while I wasn’t looking?)

Yes I read the paper that comes w it explaining the pill but im still kinda worried n just wanna know whether I can skip my period completely because of the plan b and whether or not my period can be later than a week without being pregnant.

Also please don’t tell me this wasn’t an emergency or just negative stuff. I decided to make a decision when I wasn’t sure whether a condom broke, better safe than sorry.