Inserting Node into middle of Linked List, and accidentally inserting null node as well

I'm working on a program that does not use Java's built in Linked List class; I'm building it from scratch. I've been successful with everything except writing a method that inserts a Node into a particular position of the linked list.

I have a method that sets a particular Node as the "current" Node. So, for example, I have a linked list that looks like this: cats --> dogs --> make --> good --> pets, and "current" is equal to 2; that means that the "current" Node is "dogs".

From here, let's say I want to insert a new Node at the position of "current" whose info field reads and. If done correctly, the final linked list will be: cats --> and --> dogs --> make --> good --> pets; "and" will replace "dogs" at position 2.

So here's my problem: my method works to insert a new Node at position two, but something's going wrong with linking the newly created node to pre-existing nodes. Not only am I inserting my new node into the list, but I'm also inserting a node with no information before "dogs". As my code currently runs, the output looks like this: cats --> and --> (blank) --> dogs --> make --> good --> pets.

I'm 99.9% sure the problem lies in the (if current != null) portion of the code, I just can't figure out how to fix it.

Any thoughts on why I'm inserting a blank node in addition to the node I actually want to add?

public void insert () {

    System.out.println("Please enter the text you wish to insert, or type \"end\" if you are done inserting.");
    String theString;
    theString = console.nextLine();

    while (!theString.equals("end")){
        newNode = new Node ();
        newNode.info = t