more bleeding?? TMI

hi ladies!

so at 4 weeks pp, i had my first period since my c section. it

lasted 5 days and was like any other period if not better. however, two days after my period i took plan b and three days following that i started spotting and now i’m full on heavy bleeding, passing large clots and having to wear period underwear because tampons cannot handle it. is this normal? this is my first baby and first time taking plan b so i’m not sure what to expect. TIA!