Help!!!

So I️ was suppose to get my period last week and I️ had a infection and was spotting but I️ dont know if I️t was for that reason or if I’m pregnant but anyways I️ took a plan b pill last time for my period and I️t came I️ wanted to know if a plan b pill can mess up your cycle after taking I️t one time. I️ have also had my period symptoms for like 4 days but I️ haven’t got my period.