Checkboxes based on user id it save's only one id from all the checkboxes

I have a form with 10 checkboxes based on user id, but when i check a box in my database i see that only user id 1 checkbox is saving.. please see my code below, any help appreciated!

HTML:

<form method="post" action="" id="prezente" uid="<?php echo $row['id'];?>">

     <input type="checkbox" name="day1" id="day1" value="1" class="form-check-input">

     <input type="checkbox" name="day2" id="day2" value="1" class="form-check-input">

     <input type="checkbox" name="day3" id="day3" value="1" class="form-check-input">

And so on until day10 ..
</form>

Javascript:

$(document).ready(function(){

$('#day1,#day2,#day3').click(function(){

   var id = $('#prezente').attr('uid');
   var day1 = $('input[name=day1]:checked').val();
   var day2 = $('input[name=day2]:checked').val();
   var day3 = $('input[name=day3]:checked').val();

            $.ajax({
                url: 'sql/add-days.php?uid='+id,
                type: 'post',
                data: { day1: day1,day2: day2,day3: day3 },
                success:function(data){
                  alert("success");
                }
            });
        });
});

add-days.php file:

// Make a MySQL Connection
$db = mysqli_connect("localhost", "stelelea_anapp", "fidodido", "stelelea_anadanceapp");

$day1 = $_POST['day1'];
$day2 = $_POST['day2'];
$day3 = $_POST['day3'];

$uid = $_GET['uid'];

 $query = mysqli_query($db,"UPDATE `inscrieri` SET day1='$day1',day2='$day2',day3='$day3' WHERE id = $uid");