pagination displaying same results for all links

[reddyink]

I have pagination code working properly for count and no of pages and limit. When I click on 2nd 3rd and 4rth pages same results are displayed. Can anybody please explain what am I missing
I really appreciate any help.
Code starts here.....
$limit = 2 ;
$count = $db->query_first("select count(*) count query");

$count['count'] = vb_number_format($count['count']);
$totalrows = $count['count'];

if(empty($page))
{
$page = 1;
}
$limitvalue = $page * $limit - ($limit);
$query = "My query";
$getusercats = $db->query_read($query);
while($cats = mysql_fetch_array($getcats)){

eval('$cats .= "' . fetch_template('mainforum_navpage') . '";');
}

//Start pagination code here
// by default we show first page
$pageNum = 1;

// if $_GET['page'] defined, use it as page number
if(isset($_GET['page']))
{
$pageNum = $_GET['page'];
}

if(!isset($_GET['page'])){

$page = 1;

} else {

$page = $_GET['page'];

}
$pagenum = intval($page);
if (!isset($pagenum))
{
$pagenum = 1;
}

// counting the offset
$offset = ($pageNum - 1) * $limit;

$numrows = $count['count'];

// how many pages we have when using paging?
$maxPage = ceil($numrows/$limit);

// print the link to access each page
$self = $_SERVER['PHP_SELF'];
$nav = '';

for($page = 1; $page <= $maxPage; $page++)
{
if ($page == $pageNum)
{
$nav .= " $page "; // no need to create a link to current page
}
else
{
$nav .= " <a href=\"$self?page=$page\">$page</a> ";
}
}
if ($pageNum > 1)
{
$page = $pageNum - 1;
$prev = " <a href=\"$self?page=$page\">[Prev]</a> ";

$first = " <a href=\"$self?page=1\">[First Page]</a> ";
}
else
{
$prev = '&nbsp;'; // we're on page one, don't print previous link
$first = '&nbsp;'; // nor the first page link
}

if ($pageNum < $maxPage)
{
$page = $pageNum + 1;
$next = " <a href=\"$self?page=$page\">[Next]</a> ";

$last = " <a href=\"$self?page=$maxPage\">[Last Page]</a> ";
}
else
{
$next = '&nbsp;'; // we're on the last page, don't print next link
$last = '&nbsp;'; // nor the last page link
}