How to clamp Y rotation of camera?

Hi! So, i am trying to make a third person shooter and i have the movement/ camera script done, but i have one little problem. When i press right-click to aim, i cant clamp the y rotation of the camera and i can rotate the camera 360 degrees. Also the values are weird, when the camera goes up the x descends, and when the camera goes down the x value gets bigger.

Here is the script:

private const float Y_ANGLE_MIN = 0f; private const float Y_ANGLE_MAX = 50f;

 public Transform lookAt;
 public Transform cameraTransform;
 public Transform shootPoint;
 public float rotationSpeed;
 public bool isShooting;

 private Camera cam;

 private float distance = 5f;
 private float currX = 0f;
 private float currY = 0f;
 private float mouseX = 0f;
 private float mouseY = 0f;

 private void Start()
 {
     Cursor.lockState = CursorLockMode.Locked;

     cameraTransform = transform;
     cam = Camera.main;
 }

 private void Update()
 {
     currX += Input.GetAxis("Mouse X") * rotationSpeed;
     currY += Input.GetAxis("Mouse Y") * rotationSpeed * -1f;

     currY = Mathf.Clamp(currY, Y_ANGLE_MIN, Y_ANGLE_MAX);

     if(Input.GetKey(KeyCode.Mouse1))
     {
         if(isShooting == false)
         {
             cameraTransform.rotation = Quaternion.Euler(0, lookAt.rotation.eulerAngles.y, 0);
         }
         isShooting = true;
         cameraTransform.position = shootPoint.position;

         mouseX = Input.GetAxis("Mouse X") * rotationSpeed;
         cameraTransform.Rotate(mouseX * Vector3.up, Space.World);
         lookAt.Rotate(mouseX * Vector3.up);

         mouseY = Input.GetAxis("Mouse Y") * rotationSpeed * -1f;
         cameraTransform.Rotate(mouseY * Vector3.right, Space.Self);
     }
     if(Input.GetKeyUp(KeyCode.Mouse1))
     {
         isShooting = false;
     }
 }

 private void FixedUpdate()
 {
     if (isShooting == false)
     {
         Vector3 dir = new Vector3(0, 0, -distance);
         Quaternion rotation = Quaternion.Euler(currY, currX, 0);
         cameraTransform.position = lookAt.position + rotation * dir;
         cameraTransform.LookAt(lookAt.position);
     }
 }

I would be glad if someone could help me out :)!