Problems with add() and remove() in my Doubly Circular Linkedlist code

Question

I have been working on this code for 6 hours and some how it won't remove correctly when the list has 0,2,4 elements.
It will attempt to remove element at index 0 but actually removed 4. I thought it was the reference problem at first, so i did something to my add() method so that it reference head to tail, tail to head. But still, the code doesn't work.
The problem seem to be how to remove the element at index 0. If anyone has any ideas, please let me know.
Add:
public void add(T item) {
          if (isEmpty()){     
               Node<T> n = new Node<T> (null,item,null);     
               head = n;
               tail = n;
               head.setNext(tail);
               head.setPrev(tail);
               tail.setNext(head);
               tail.setPrev(head);
          else{
               Node<T> n = new Node<T> (tail,item,head);
               n.getPrev().setNext(n);
               tail=n;
               head.setPrev(tail);
               tail.setNext(head);
          size++;
     }Remove:
public T removeAt(int index) {
          Node<T> target = getNode(index);
          //System.out.println(target.getValue());
          if (index>size()||index<0){
               throw new IllegalArgumentException
                    ("Can't remove anything out of the list.");
          if (isEmpty()){
               throw new NoSuchElementException
                    ("Can't remove from empty list.");
          }else {
               if (target.getNext().equals(target.getPrev())){
                    target.getNext().setNext(null);
                    target.getPrev().setPrev(null);
               }else{
               System.out.println("target prev: "+ target.getPrev().getValue());
               System.out.println("target: " + target.getValue());
               System.out.println("target next: "+ target.getNext().getValue());
               target.getPrev().setNext(target.getNext());
               target.getNext().setPrev(target.getPrev());
               size--;
          return target.getValue();
     }

Answer 1

size won't ever reach -1 since it won't -1 if isEmpty() returns true in getNode().
The procedure is, if I can get the node, i will try to remove it, if i can't even get it, nothing will run in removeAt (idx) except the first line.
public T removeAt(int index) {
          Node<T> target = getNode(index);
          if (size()==1){
               head=tail=null;
               size=0;     
               return null;
          }else if (size()==2){
               if (index==0)                      // first but not the last.
                    target.getNext().setPrev(null);
                    target.getNext().setNext(null);
               if (index==1)                   // last but not the first.
                   target.getPrev().setPrev(null);
                    target.getPrev().setNext(null);
          }else{
                    System.out.println("target prev: "+ target.getPrev().getValue());
                    System.out.println("target: " + target.getValue());
                    System.out.println("target next: "+ target.getNext().getValue());
                    target.getNext().setPrev(target.getPrev());
                    target.getPrev().setNext(target.getNext());
               size--;          
          return target.getValue();
     }