Untitled

<body>
  <p class = 'myp'>this is my p</p>
</body>

$(function(){
      $('p.myp').after('<div class = "firstDiv">first div added with jquery</div>');
      $('p.myp').after('<div class = "secondDiv">second div added with jquery</div>');
      console.log($('p.myp').next('div.firstDiv').text());

      console.log($('p.myp').next('div.secondDiv').text());
    });

<body>
  <p class="myp">this is my p</p>
  <div class="secondDiv">second div added with jquery</div> <!-- this is next -->
  <div class="firstDiv">first div added with jquery</div> <!-- this is not -->
</body>

$(function () {
    var first = $('<div />', {
        'class' : 'firstDiv',
        text    : 'first div added with jquery'
    });
    var second = $('<div />', {
        'class' : 'secondDiv',
        text    : 'second div added with jquery'
    });

    $('p.myp').after(first);
    $('p.myp').after(second);

    console.log(first.text());
    console.log(second.text());
});

<p class="myp">this is my p</p>

$('p.myp').after('<div class="firstDiv"></div>');

<p class="myp">this is my p</p>
<div class="firstDiv"></div>

$('p.myp').after('<div class="secondDiv"></div>');

<p class="myp">this is my p</p>
<div class="secondDiv"></div>
<div class="firstDiv"></div>