Trying to lock camera's Y axis and it's resetting at 0 degrees

So I'm trying to make a basic controller and I'm using Mathf.Clamp() to try to stop the camera from rotating around in circles and now it's just resetting the rotation of the camera every time it hits 0 and I have no idea why.

GIF: https://gyazo.com/ba2b7093225a039dfca980b089298ce8

Code: float h = horizontalSpeed Input.GetAxis("Mouse X"); //float v = verticalSpeed Input.GetAxis("Mouse Y");

     transform.Rotate(0, h, 0);

     Vector3 rot = playerCamera.transform.eulerAngles;
     float mouseY = Input.GetAxis("Mouse Y") * verticalSpeed;
     rot.x = Mathf.Clamp(rot.x + mouseY, -limit, limit);
     playerCamera.transform.eulerAngles = rot;