Is it my period or implantation ?

On dec 20 I had unprotected sex and dec 21 I then took plan b in between the same time period (24 hour pill window ) on dec 26 I got my (period) which idk if it is , it came early ( day 23 cycle ) idk if maybe the plan b effected me , but I have the worst cramps where I feel like crying , my cramps are worsening by the min it’s not mild it’s worse. And I’m bleeding very little and I have these lil clumps ir clots, they are pink and red idk what that means . I’m worried maybe it’s implantation but my cramps are so bad... could it be my period just starting very slow and painfully idk SOMEONE HELP