I made an infinite recursion but I don't know how to fix it.

So, I'm making a procedurally generated roguelike rpg game and I'm stuck trying to get procedural generation. I've never made a procedurally generated game before so I don't know if there is a better way to do this but this is how I did it:

Basically I'm trying to generate rooms in random configurations by making a linked list (or tree?) class. So I have a class Room with reference to 4 rooms, topRoom, rightRoom, leftRoom and bottomRoom. The Room class also has a vector 3 for position and that's all the significant properties it has right now. The constructor takes in just a vector 3 for position. Then I have a static class called LevelBuilder which does what it says, builds levels out of this room class. Here it is. The basic premise is:

1- Get an array of all the possible locations for rooms from a single room (top, right, bottom, left) 2- Loop through the array and find if there is a room at any of those locations 3- If there is not a room, generate a probability of spawning one and test it, the probability will be dependent on the distance from the origin in a particular direction. So the chance of creating another room to the top goes down the further up we go. Same with right, left, etc. 4- If a room has been created, repeat from step (1) on that room

 public static class LevelBuilder
 {
     public static void build(Room source)
     {
         Room[] clockwise = { source.top, source.right, source.left, source.bottom };
         int checker = 0;
         Vector2 possibleRoom = Vector2.zero;
         for (int i = 0; i < clockwise.Length; i++)
         {
             Room current = clockwise[i];
             if (current is null)
             {
                 if (i == 0)
                 {
                     
                     possibleRoom = source.position + new Vector3(0, 10, 0);
                     float topChance = Mathf.Pow(0.7f, possibleRoom.y / 10) * 100;
                     checker = Random.Range(0, 100);
                     if (topChance > checker && Physics2D.OverlapPoint(possibleRoom) == null)
                     {
                         source.top = new Room(possibleRoom);
                         build(source.top);
                     }
                 }
                 if (i == 1)
                 {
                     possibleRoom = source.position + new Vector3(10, 0, 0);
                     float rightChance = Mathf.Pow(0.7f, possibleRoom.x / 10) * 100;
                     checker = Random.Range(0, 100);
                     if (rightChance > checker && Physics2D.OverlapPoint(possibleRoom) == null)
                     {
                         source.right = new Room(possibleRoom);
                         build(source.right);
                     }
 
                 }
                 if (i == 2)
                 {
                     possibleRoom = source.position + new Vector3(0, -10, 0);
                     float bottomChance = Mathf.Pow(0.7f, -possibleRoom.y / 10) * 100;
                     checker = Random.Range(0, 100);
                     if (bottomChance > checker && Physics2D.OverlapPoint(possibleRoom) == null)
                     {
                         source.bottom = new Room(possibleRoom);
                         build(source.bottom);
                     }
                }
                 if (i == 3)
                 {
                     possibleRoom = source.position + new Vector3(-10, 0, 0);
                     float leftChance = Mathf.Pow(0.7f, -possibleRoom.x / 10) * 100;
                     checker = Random.Range(0, 100);
                     if (leftChance > checker && Physics2D.OverlapPoint(possibleRoom) == null)
                     {
                         source.left = new Room(possibleRoom);
                         build(source.left);
                     }
                 }
             }
         }
     }
 
 }
 

It's either this code is wrong or the part where I instantiate the rooms goes into an infinite loop (also recursion)

I get this error: The requested operation caused a stack overflow and it points to the build function