Дублирует сообщения при обновлении страницы

Доброго времени суток , возникла проблема , при отправке сообщения , потом если обновить страницу , оно дублируется ( в датабазу тоже дублируется ) Код прилагаю . Помогите пожалуйста

Код (Text):

1. <?php
2. session_start();
3. ini_set('display_errors', 'on');
4. require_once("./Connector/DbConnectorPDO.php");
5. require("./helper/helperFunctions.php");
6. $userId = isset($_SESSION["userId"]) && !IsVariableIsSetOrEmpty($_SESSION["userId"]) ? $_SESSION["userId"] : 0;
7. $connection = getConnection();
8. $userObj = $userId !== 0 && !IsVariableIsSetOrEmpty($_SESSION["user"]) ? $_SESSION["user"] : "";
9. $msgList = [];
10. $recentMsgList = [];
11. $msgToUserId = isset($_GET["id"]) && !IsVariableIsSetOrEmpty($_GET["id"]) ? $_GET["id"] : 0;
12.  
13. if (isset($_POST["SendMessage"]) && !IsVariableIsSetOrEmpty($_POST["SendMessage"])) {
14.     $msg = $_POST["msg"];
15.     if (isset($msg) && !IsVariableIsSetOrEmpty($msg)) {
16.         $insertMessageQuery = "INSERT INTO messages(msg_from_user_id,msg,msg_to_user_id,msg_date,is_msg_read)
17.                                values(:userId,:msg,:msgToUserId,NOW(),0)";
18.         $insertStmt = $connection->prepare($insertMessageQuery);
19.         $insertStmt->bindParam(':userId', $userId);
20.         $insertStmt->bindParam(':msg', $msg);
21.         $insertStmt->bindParam(':msgToUserId', $msgToUserId);
22.         $insertStmt->execute();
23.        
24.     }
25.  
26. }
27.  
28. if ($userId === 0 || (!isset($_GET["id"]) && !isset($msgToUserId))) {
29.     header("location:./view-profiles.php");
30.     exit;
31. }
32.  
33. if ($msgToUserId !== 0) {
34.  
35.     $recentMsgQuery = "SELECT
36.     *
37. FROM
38.     (
39.     SELECT profile
40.         .id,
41.         profile.firstName,
42.         profile.lastName,
43.         profile.imgUrl,
44.         (
45.         SELECT
46.             msg
47.         FROM
48.             messages
49.         WHERE
50.             messages.msg_from_user_id = profile.id OR messages.msg_to_user_id = profile.id
51.         ORDER BY
52.             id
53.         DESC
54.     LIMIT 1
55.     ) AS lastMessage,
56.     (
57.     SELECT
58.         msg_date
59.     FROM
60.         messages
61.     WHERE
62.         messages.msg_from_user_id = profile.id OR messages.msg_to_user_id = profile.id
63.     ORDER BY
64.         id
65.     DESC
66. LIMIT 1
67. ) AS msgDate
68. FROM profile
69. WHERE
70.     id <> :userId
71. ) X
72. LEFT JOIN (
73.     Select DISTINCT ids
74.     from (
75.             select msg_from_user_id as ids
76.             from messages
77.             where msg_from_user_id =:userId  or msg_to_user_id=:userId
78.             UNION
79.             select msg_to_user_id as ids
80.             from messages
81.             where msg_from_user_id =:userId  or msg_to_user_id=:userId
82.         )uniqueIdList
83.         where ids <> :userId
84.    )IdList on X.id=IdList.ids
85. WHERE
86.     ids IS NOT NULL
87.     AND
88.     lastMessage IS NOT NULL
89.     ORDER BY msgDate desc";
90.     $recentQueryStmt = $connection->prepare($recentMsgQuery);
91.     $recentQueryStmt->bindParam(':userId', $userId);
92.     $recentQueryStmt->execute();
93.     $recentMsgList = $recentQueryStmt->fetchAll();
94.    
95.  
96.  
97.     $query = "SELECT m.id as msg_id
98.       ,msg_from_user_id
99.       ,msg_to_user_id
100.       ,msg
101.       ,msg_date
102.       ,is_msg_read
103.       ,msg_read_date
104.       ,fromUser.id as fromUserId
105.       ,fromUser.firstName as fromFirstName
106.       ,fromUser.lastName as fromLastName
107.       ,fromUser.imgUrl as fromUserImgUrl
108.       ,toUser.id as toUserId
109.       ,toUser.firstName as toUserFirstName
110.       ,toUser.lastName as toUserLastName
111.       ,toUser.imgUrl as toUserImgUrl
112. FROM messages m
113. left join profile as fromUser on m.msg_from_user_id=fromUser.id
114. left JOIN profile as toUser on m.msg_to_user_id=toUser.id
115. WHERE (msg_from_user_id =:userId and msg_to_user_id=:sentToUserID) or (msg_from_user_id=:sentToUserID and msg_to_user_id=:userId)";
116. //ORDER BY msg_date DESC";
117.  
118.     $stmt = $connection->prepare($query);
119.     $stmt->bindParam(':userId', $userId);
120.     $stmt->bindParam(':sentToUserID', $_GET["id"]);
121.     $stmt->execute();
122.     $msgList = $stmt->fetchAll();
123.    
124.  
125.     if (count($msgList) > 0) {
126.         $lastMsgRow = end($msgList);
127.         if ($lastMsgRow["msg_from_user_id"] === $msgToUserId && $lastMsgRow["msg_to_user_id"] === $userId && intval($lastMsgRow["is_msg_read"]) === 0) {
128.             $updateAllMsgReadQuery = "UPDATE messages set is_msg_read=1,msg_read_date=NOW() where msg_from_user_id=:sentToUserID and msg_to_user_id=:userId and is_msg_read=0";
129.             $stmt = $connection->prepare($updateAllMsgReadQuery);
130.             $stmt->bindParam(':sentToUserID', $msgToUserId);
131.             $stmt->bindParam(':userId', $userId);
132.             $stmt->execute();
133.            
134.         }
135.     }
136. }
137.  
138. ?>