Could The Plan B Pill Cause Hormonal Imbalance?

hi i am 23 and i am sexually active in april my boyfriend and i had unprotected sex and i took the plan b pill since then my period is completely out of whack, i know this is a possiblily because of the hormonal inbalance it creates but my question is how long till it should be back to regular it is super light almost non exisistant??