URL Rewrite issue after submit - php

Question

I succesfully managed to add to my url an parameter but I can't increment it. For example, if I click on the submit button the url should transform from http://localhost/code/1 to http://localhost/code/2 . I have made an input hidden to access the url but I can't redirect it to the desired value, how can I do this? This is my PHP code:
<?php
$cod=strtoupper($_GET['params']);
$i=$_GET['params1'];
$id_rezervare="SELECT id FROM trezervare WHERE numar_rezervare = '$cod'";
$id_rezervare = $db->DbGetOne($id_rezervare);
$cod_rezervare="SELECT UPPER(numar_rezervare) FROM trezervare WHERE numar_rezervare = '$cod'";
$cod_rezervare = $db->DbGetOne($cod_rezervare);
$cod_rezervare1 = strtoupper($cod_rezervare);
$nr_camere="SELECT count(*) FROM trezervarecont WHERE idrezervare= $id_rezervare ";
$nr_camere = $db->DbGetOne($nr_camere);
$checkin_status=TRUE;
$actual_link = "http://$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]";
$data_nasterii= $_GET['datanasterii'];
$test_arr = explode('/', $data_nasterii);
if(isset($_POST['trimite'])){
if (count($test_arr) == 3) {
if (checkdate($test_arr[0], $test_arr[1], $test_arr[2])) {
} else {
$message = "Date has an invalid format";
echo "<script type='text/javascript'>alert('$message');</script>";
}
} else {
$message = "No date selected";
echo "<script type='text/javascript'>alert('$message');</script>";
}
}
if(isset($_POST['trimite'])){
$i++;
}
?>
<div class="animated fadeOutZoom">
<div class="container container-sm animated fadeInDown">
<div class="center-block mt-xl">
<div class="panel">
<div class="panel-body">
<p class="pv text-bold">Check-in for room number <?php echo $i; ?></p>
<form action="" method="post">
<div class="row">
<div class="col-md-12 form-group">
<label for="nume">Nume</label>
<input type="text" id="text " class="form-control " name="nume" >
</div>
<input type="hidden" id="custId" name="checkin_status" value="<?php echo 1;?>">
<input type="text" id="custId" name="checkin_status" value="<?php echo $actual_link;?>">
<div class="col-md-12 form-group">
<label for="nume">Data Nasterii</label>
<input type="text" class="form-control" id="arrival_date" name="datanasterii"required/>
</div>
<div class="col-md-12 form-group">
<label for="nume">Locul nasterii</label>
<input type="text" id="text "class="form-control " name="loculnasterii" required>
</div>
<div class="col-md-12 form-group">
<label for="nume">Cetatenia</label>
<input type="text" id="text "class="form-control " name="cetatenie" required>
</div>
<div class="col-md-12 form-group">
<label for="nume">Localitate</label>
<input type="text" id="text "class="form-control " name="localitate" required>
</div>
<div class="col-md-12 form-group">
<label for="nume">Strada</label>
<input type="text" id="text "class="form-control " name="strada" required>
</div>
<div class="col-md-12 form-group">
<label for="nume">Numar strada</label>
<input type="text" id="text "class="form-control " name="nrstrada" required>
</div>
<div class="col-md-12 form-group">
<label for="nume">Tara</label>
<input type="text" id="text "class="form-control " name="tara" required>
</div>
<div class="col-md-12 form-group">
<label for="nume">Tip act</label>
<input type="text" id="text "class="form-control " name="tipact" required>
</div>
<div class="col-md-12 form-group">
<label for="nume">Serie act</label>
<input type="text" id="text "class="form-control " name="serieact" required>
</div>
<div class="col-md-12 form-group">
<label for="nume">Numar act</label>
<input type="text" id="text "class="form-control " name="nract" required>
</div>
</div>
<div class="row">
<div class="col-md-12 form-group">
<label for="telefon">Telefon</label>
<input type="phone" id="telefon " class="form-control " name="telefon" required>
</div>
</div>
<div class="row">
<div class="col-md-12 form-group">
<label for="email">Email</label>
<input type="email" id="email" class="form-control" name="email" required >
</div>
</div>
<div class="row">
<div class="col-md-6 form-group">
<?php if($i==$nr_camere) echo'
<input type="submit" value="Finalizeaza rezervarea" class="btn btn-primary" name="trimite">';
elseif ($i>$nr_camere) {
header("location:../finalizeaza.php");
}
else echo ' <input type="submit" value="Continua rezervarea" class="btn btn-primary" name="trimite">';
?>
</div>
</div>
</form>
</div>
</div>
</div>
</div>
</div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-datepicker/1.8.0/js/bootstrap-datepicker.min.js"></script>
<script>
//$('#arrival_date, #departure_date').datepicker({format: 'yyyy/mm/dd'});
$('#arrival_date, #departure_date').datepicker({
format: 'yyyy-mm-dd',
endDate: '+0d',
minDate: '-120Y',
autoclose: true
});
</script>