Plan b effects people in different ways. One of my friends took it and it made her start her period a couple days later. When I took it once I got my period on time but it made me crampy and extremely nauseous. I was afraid it didn't work or something but realized it was just effecting my body differently.
& its ok if you're not spotting, i didn't spot at all after taking plan b, but my period came a week later
I can say that plan b either delays your period or makes it come earlier, its OK to have cramps, if your period doesnt come in 2 weeks take a pregnancy test,