SmoothDamp not going to target position

I'm trying to smoothly change my cameras position and I'm having trouble with smoothdamp. My code works how I want it to if I just set the new position of the camera instantly, but when I try to use the SmoothDamp method the camera goes mostly to ground level and is shaking. Here's my script.

using UnityEngine; using System.Collections;

public class SmoothFollow : MonoBehaviour {

 // The target we are following
 public Transform target;
 // The distance in the x-z plane to the target
 public float distance = 10.0f;
 // the height we want the camera to be above the target
 public float height = 5.0f;
 // How much we 
 public float heightDamping = 2.0f;
 public float rotationDamping = 3.0f;
 public float posDamp = 100f;
 public float smoothTime = 0.3f;

 Vector3 velocity = Vector3.zero;

 Vector3 mousePos;
 // Place the script in the Camera-Control group in the component menu
 [AddComponentMenu("Camera-Control/Smooth Follow")]

 void LateUpdate()
 {
     // Early out if we don't have a target
     if (!target) return;

     // Calculate the current rotation angles
     float wantedRotationAngle = target.eulerAngles.y;
     float wantedHeight = target.position.y + height;

     float currentRotationAngle = transform.eulerAngles.y;
     float currentHeight = transform.position.y;

     // Damp the rotation around the y-axis
     currentRotationAngle = Mathf.LerpAngle(currentRotationAngle, wantedRotationAngle, rotationDamping * Time.deltaTime);

     // Damp the height
     currentHeight = Mathf.Lerp(currentHeight, wantedHeight, heightDamping * Time.deltaTime);

     // Convert the angle into a rotation
     var currentRotation = Quaternion.Euler(0, currentRotationAngle, 0);

     // Set the position of the camera on the x-z plane to:
     // distance meters behind the target
     transform.position = target.position;
     transform.position -= currentRotation * Vector3.forward * distance;

     mousePos = Input.mousePosition;
     mousePos.x -= Screen.width / 2;
     mousePos.y -= Screen.height / 2;
     
     Vector3 newPos = transform.TransformPoint((mousePos.x / posDamp), 0, transform.position.z + (mousePos.y / (posDamp / 1.5f)));
     newPos = new Vector3(transform.position.x + (mousePos.x / posDamp), currentHeight, transform.position.z + (mousePos.y / (posDamp / 1.5f)));
     Debug.Log(newPos);

     // Set the height of the camera
     //transform.position = new Vector3(transform.position.x + (mousePos.x / posDamp), currentHeight, transform.position.z + (mousePos.y / (posDamp / 1.5f)));

     //// Set the height of the camera
     transform.position = Vector3.SmoothDamp(transform.position, newPos, ref velocity, smoothTime);
 }

}

I tried setting the vector using transform point and then I tried to just create a new vector3. Neither worked.