Plan B is not mean to be used as regular birth control because the dose is far higher than the regular
birth control pill and therefore a far greater risk of
side effects. It was never meant to be used regularly, just in case of emergency like broken condom, hence why they call it Emergency contraception.
There are many different birth control options such as the birth control pill, patch, ring, IUD, Depo shot. I've used the pill for over 15 years with no lasting issues.