Camera rotating by itself to the left

im trying to make a game and so far its going good and im having a problem where the camera is slowly rotating to the left by itself and as time goes by it gets faster and faster, so far ive tried everything i know and could find and i cant fix the issue, if anyone could help that would be amazing
this is the code for player rotation:

    private float desiredX;

    private void Look()
    {
        float mouseX = Input.GetAxis("Mouse X") * sensitivity * Time.fixedDeltaTime * sensMultiplier;
        float mouseY = Input.GetAxis("Mouse Y") * sensitivity * Time.fixedDeltaTime * sensMultiplier;

        //Find current look rotation
        Vector3 rot = playerCam.transform.localRotation.eulerAngles;
        desiredX = rot.y + mouseX;

        //Rotate, and also make sure we dont over- or under-rotate.
        xRotation -= mouseY;
        float clamp = 89.5f;
        xRotation = Mathf.Clamp(xRotation, -clamp, clamp);

        //Perform the rotations
        playerCam.transform.localRotation = Quaternion.Euler(xRotation, desiredX, 0);
    }