how to format bootstrap

i am currently editing my login page and i found that my bootstrap icon is not align as useame.it supposed to be center but now it is slightly up in the useame box field. how to edit to be center.

2. secondly, how to set if the first time reload to the page, the icon not displayed until i start to type useame.

   <h3 class="form-title">Login to your account</h3>
                   <div class="alert alert-danger display-hide">
                     <button class="close" data-close="alert"></button>
                   </div>
                       <div class="form-group has-feedback" ng-class="loginForm.useame.$valid ? 'has-success' : 'has-error';">
                           <label class="control-label" for="useame">Useame</label>
                           <input type="text" class="form-control" id="useame" name="useame"
                                  ng-model="input.useame" required>
                           <span class="glyphicon form-control-feedback"
                                 ng-class="loginForm.useame.$valid ? 'glyphicon-ok' : 'glyphicon-remove';"></span>
                       </div>
   
   

   my login picture