Slerp camera rotation moves on it's own at runtime?

I have a script to rotate the camera with an input axis, it works mostly. The big problem is that it starts moving on run time without input, and when I use the input, it eventually resists going further, and drifts back to centre. Trying to figure out how to stop this, so the input axis just rotates the camera normally without restriction, but does nothing when no input is used...? I am beginner to C#, but am trying my hardest to learn.

there is a rigid body attached to the camera, set to no gravity, no drags, and mass of 1.

the axis inputs are set to gravity and sensitivity 3, and dead at 0.005.

the camera has one child, which is a light.

Any input is appreciated! Danke! ; D

 using UnityEngine;
 using System.Collections;
 
 public class control_rotator : MonoBehaviour {
 
 
     //rotate variables
 
     public float horizontalSpeed = 0.3F;
     public float verticalSpeed = 0.3F;
 
     public float speed = 0.3f;
     public Transform target; // set to the main camera (itself)
 
     //movement variables
 
     public float moveSpeed = 3.0f;
 
     void Update() {
 
 
         // input and transform rotation values
 
         float h = horizontalSpeed * Input.GetAxis("Horizontal2");
         float v = verticalSpeed * Input.GetAxis("Vertical2");
         transform.Rotate(-v, -h, 0);
 
 
         //locate and slerp rotation values
 
         Vector3 relativePos = target.position - transform.position;
         Quaternion where = Quaternion.LookRotation(relativePos);
 
         transform.rotation = Quaternion.Slerp(transform.rotation, where, Time.deltaTime * speed);
 
         // input and transform movement values
 
         float moveHorizontal = moveSpeed * Input.GetAxis ("Horizontal");
         float moveVertical = moveSpeed * Input.GetAxis ("Vertical");
 
         //movement vectors and physics
         
         Vector3 movement = new Vector3 (moveHorizontal, 0.0f, moveVertical);
     
         rigidbody.velocity = movement * moveSpeed;
 
 
 
 
 
 }
 }