navigation of months missing months with 30days

[idlerob]

Hi i have a navigation bar of months that is used to display news stories for that month, though today the months arent displaying properly which im guessing is because its a month with 31days so only the months with 31 days are showing

heres the code, it gets the news stories from the database and then creates the navigation

 

$page = "news";
if ( $_GET["s"] != "" ) {
$query = "SELECT headline, headline_image, headline_imagealt, full_story, news_date FROM news WHERE ID = ".$_GET["s"]." LIMIT 1;";
$story = mysql_fetch_object( mysql_query( $query ) );
} else {
if ( $_GET["m"] == "" ) {
	$limit = " LIMIT 5";
	$where = "";
} else {
    $limit = "";
	$start_date = $_GET["m"]."-01";
    $end_date = date( "Y-m-d", strtotime( $start_date." +1 month" ) ); 
	$where = " AND news_date >= '".$start_date."' AND news_date < '".$end_date."' ";
}
    // GET MAIN NEWS STORIES
    $query = "SELECT ID, headline, headline_image, headline_imagealt, full_story, news_date, more_info FROM news WHERE status_codeID = '2'".$where." ORDER BY news_date DESC".$limit.";";
$result = mysql_query( $query );
}

<div id="subnav">
		<p>
		<?php
		for ( $i=0; $i<6; $i++ ) {
                $_GET["m"] == date( "Y-m", strtotime( "-".$i." months" ) ) ? $selected = " curpage" : $selected = "";
			$i==0 ? $class=" class=\"first".$selected."\"" : $class=" class=\"".$selected."\"";
			print "<a href=\"whats_new.php?m=".date( "Y-m", strtotime( "-".$i." months" ) )."\"".$class.">".date( "F", strtotime( "-".$i." months" ) )."</a>";
		}
		?>
		</p>
        </div>

 

so today my navigation is missing out the months with 30days (november, september etc)

any help would be great thanks