Still no period after plan B ?

I took plan B three weeks ago on monday. Still no period. It says to take a pregnancy test if its been 3 weeks and no period. Has this happened to anyone else ? Where you don’t bleed for a while after plan B but you still weren’t pregnant? I did take plan B in the beginning of april too...so maybe two plan Bs in a 30 day period is fucking me up too. Don’t worry, i’ve learned my lesson and saw my gyno and left that day with a bag of birth control but she told me to wait to start them until I get a period so i’m waiting and not having sex. But Do i need to test or just keep waiting it out ? I keep feeling like i’m about to start my period but nothing comes out 🙄 When should I test ?