Count Consecutive Days of Absence Per Staff

In C2 then copy down

=IFERROR(IF(INDEX($B$1:$B1,AGGREGATE(14,6,ROW($A1:$A$2)/($A1:$A$2=$A2),1))=$B2-1,"Y","N"),"N")

In D2 then copy down

=IF(C2="N","",SUMPRODUCT(--(INDEX($A$1:$A2,AGGREGATE(14,6,ROW($A$1:$A2)/(($A$1:$A2=$A2)*($C$1:$C2="N")),1)):$A2=$A2)))