<?php

$output ="";
    $semana = array(

    '1' => 'Segunda-Feira',
    '2' => 'Terca-Feira',
    '3' => 'Quarta-Feira',
    '4' => 'Quinta-Feira',
    '5' => 'Sexta-Feira',
    '6' => 'Sábado',
    '7' => 'Domingo'
);

$a = array_slice($semana, date('w') - 1 );

$b = array_slice($semana, 0 , date('w') - 1 );

$c = array_merge_recursive( $a , $b );

foreach( $c as $key => $value ) {

    $output = $output . "\n". $value ;
}


echo $output;