Instantiate making multiple clones - unity3d

Question

I'm making a building system in my game and the basic mechanic works but for some reason whenever I place down the object it adds incrementally more clones with every placement. The first placement creates one clone, the second placement creates two clones, the third, three clones, and so on. I fixed it for one object by moving it out of an empty game object that had all the building prefabs in the hierarchy but it only works for that.
using UnityEngine;
using UnityEngine.AI;
public class GroundPlacementController : MonoBehaviour
{
[SerializeField]
private GameObject placeableObjectPrefab;
[SerializeField]
private KeyCode newObjectHotkey = KeyCode.A;
public NavMeshObstacle nav;
private GameObject currentPlaceableObject;
private float mouseWheelRotation;
private void Update()
{
HandleNewObjectHotkey();
nav = GetComponent<NavMeshObstacle>();
if (currentPlaceableObject != null)
{
MoveCurrentObjectToMouse();
RotateFromMouseWheel();
ReleaseIfClicked();
}
}
private void HandleNewObjectHotkey()
{
if (Input.GetKeyDown(newObjectHotkey))
{
if (currentPlaceableObject != null)
{
Destroy(currentPlaceableObject);
}
else
{
currentPlaceableObject = Instantiate(placeableObjectPrefab);
}
}
}
private void MoveCurrentObjectToMouse()
{
Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
RaycastHit hitInfo;
if (Physics.Raycast(ray, out hitInfo))
{
currentPlaceableObject.transform.position = hitInfo.point;
currentPlaceableObject.transform.rotation = Quaternion.FromToRotation(Vector3.up, hitInfo.normal);
currentPlaceableObject.GetComponent<NavMeshObstacle>().enabled = false;
}
}
private void RotateFromMouseWheel()
{
Debug.Log(Input.mouseScrollDelta);
mouseWheelRotation += Input.mouseScrollDelta.y;
currentPlaceableObject.transform.Rotate(Vector3.up, mouseWheelRotation * 90f);
}
private void ReleaseIfClicked()
{
if (Input.GetMouseButtonDown(0))
{
currentPlaceableObject.GetComponent<NavMeshObstacle>().enabled = true;
print("disabled");
currentPlaceableObject = null;
print("removed prefab");
}
}
}