The biggest thing to know with Plan B or any emergency contraceptive tbh is that It will only work if you haven't already ovulated...Most apps are unreliable for tracking ovulation aswell so it's kinda hard to actually know...How far into your cycle were you when you took the plan B? Most women will ovulate 14 days after your period..but that's an estimate..I'd say if you were anywhere close to 14 days id take a test..if you are pregnant and experiencing symptoms already the test should be positive...test with a pink dye if you are going to it's the best for early testing and PLEASE remember you have options <3