Player Stops Moving When Falling Object Hits Ground

I just started on Unity a few weeks ago and I got a cube to fall from a random position, but when it hits the ground, I lose control of my player for some reason. The two are in no way connected, so I'm very confused right now. Any suggestions?

Falling Object Script:

public class CubeFall : MonoBehaviour {

 // Use this for initialization
 void Start () {

     Vector3 pos = transform.position;
     pos.x = Random.Range(-10, 10);
     pos.y = 50;
     pos.z = Random.Range(-10, 10);
     transform.position = pos;

 }
 

}

Player Controls:

public class PlayerController : MonoBehaviour {

 public float speed;
 public Text countText;
 public Text winText;

 private Rigidbody rb;
 private int count;
 void Start()
 {
     rb = GetComponent<Rigidbody>();
     count = 0;
     SetCountText();
 }

 void FixedUpdate()
 {
     float moveHorizontal = Input.GetAxis("Horizontal");
     float moveVertical = Input.GetAxis("Vertical");

     Vector3 movement = new Vector3(moveHorizontal, 0.0f, moveVertical);

     rb.AddForce(movement * speed);
 }

 void OnTriggerEnter(Collider other)
 {
     if (other.gameObject.CompareTag("Pick Up"))
     {
         other.gameObject.SetActive(false);
         count = count + 1;
         SetCountText();
         speed = count/2;
     }
 }

 void SetCountText()
 {
     countText.text = "Count: " + count.ToString();
     if (count >= 12)
     {
         winText.text = "You Win!";
     }
 }

}

Yes these are modifications I'm making based off the original Roll a Ball tutorial. :/ Super new here.