PHP: How to check if a date is today, yesterday or tomorrow

First. You have mistake in using function strtotime see PHP documentation

int strtotime ( string $time [, int $now = time() ] )

You need modify your code to pass integer timestamp into this function.

Second. You use format d.m.Y H:i that includes time part. If you wish to compare only dates, you must remove time part, e.g. `$date = date("d.m.Y");``

Third. I am not sure if it works in the same way for you, but my PHP doesn't understand date format from $timestamp and returns 01.01.1970 02:00 into $match_date

$timestamp = "2014.09.02T13:34";
date('d.m.Y H:i', strtotime($timestamp)) === "01.01.1970 02:00";

You need to check if strtotime($timestamp) returns correct date string. If no, you need to specify format which is used in $timestamp variable. You can do this using one of functions date_parse_from_format or DateTime::createFromFormat

This is a work example:

$timestamp = "2014.09.02T13:34";

$today = new DateTime("today"); // This object represents current date/time with time set to midnight

$match_date = DateTime::createFromFormat( "Y.m.d\\TH:i", $timestamp );
$match_date->setTime( 0, 0, 0 ); // set time part to midnight, in order to prevent partial comparison

$diff = $today->diff( $match_date );
$diffDays = (integer)$diff->format( "%R%a" ); // Extract days count in interval

switch( $diffDays ) {
    case 0:
        echo "//Today";
        break;
    case -1:
        echo "//Yesterday";
        break;
    case +1:
        echo "//Tomorrow";
        break;
    default:
        echo "//Sometime";
}

<?php 
 $current = strtotime(date("Y-m-d"));
 $date    = strtotime("2014-09-05");

 $datediff = $date - $current;
 $difference = floor($datediff/(60*60*24));
 if($difference==0)
 {
    echo 'today';
 }
 else if($difference > 1)
 {
    echo 'Future Date';
 }
 else if($difference > 0)
 {
    echo 'tomorrow';
 }
 else if($difference < -1)
 {
    echo 'Long Back';
 }
 else
 {
    echo 'yesterday';
 }  
?>