Please explain what happens if i take plan b everyday?

Plan B: This is a pill designed to mess with your uterine lining, so that in case there should be a fertilized egg on its way to the uterus after unprotected intercourse, it would find a poor environment for implantation. It is a larger than normal dose of a synthetic progestin, a medication linked to serious side effects - it is not for every day use.

That would be a very: bad idea. It is less effective than oral contraceptive. If you don't want to become pregnant use oral contraceptive instead of repeated use of emergency contraceptive.