the return of my period 11wks postpartum

I should had known something bad would come from working out lol yesterday I started working out with a trainer and boom my period started. Coincidence I think not lol just kidding but WTF I'm breastfeeding why is my period back!?! I hate this, I hate this, I really fucking hate this!!!!! And my baby girl is extremely fussy today like of all days c'mon ugh I haven't had a period since like May omg it's been a whole year whyyyyyy!?? Hopefully the bay makes my period better/shorter that's what happened to my mom. Ugh did I mention I hate this????