C# How to get a direction of a moving object?

So basically I'm doing a 2D-game which is from top-view and because I am pretty new to Unity and scripting in general, I don't have a clue how do I get the direction of a moving object (in this case, an enemy) so I can animate it.

I just want to know how do I know whether the object is going up, down, left or right.

This is my script at the moment. I really appreciate every helping comment, but most of all I would like to know the easiest way to know the direction.

int movementSpeed = 3; float detectionRange = 3f; Transform playerTransform; Transform myTransform;

 void Awake ()
 {
     myTransform = transform;
 }
 // Use this for initialization
 void Start () {

     playerTransform = GameObject.FindGameObjectWithTag("Player").transform;
 }


 // Update is called once per frame
 void Update () {

     if (Vector3.Distance(playerTransform.position, myTransform.position)<detectionRange)
     {
         //goes to the players' direction
         Vector3 dir = playerTransform.position-myTransform.position;
         dir.Normalize();
         myTransform.position += dir * movementSpeed * Time.deltaTime;
     }
 
 }