My cycle been on for almost two weeks after taking plan b. is this normal or should i be worried ?

Can be normal, but!: It's common to have spotting and changes in your normal cycle for a few weeks after plan B. Should you worry? Yes. Plan B is not 100% effective. Check a pg test 3 weeks after you took it. Also, worry about the possibility that you also may have gotten a std after practicing unsafe sex. Worry, too, about why in the world you did this? Whatever made you careless, avoid doing that again.