With any meditation practise it's important to throw away your expectations about how it should feel and what you should experience. And that's particularly the case with this one. It is not a problem if you don't feel loving or kind whilst doing this. It's fine and completely normal if it feels the opposite. 

Every meditation is different, every moment is unique. All you have to do is be curious and kind and allow each moment to be as it is and wish it well. And this includes noticing that there is the opposite of loving kindness, or feeling nothing whatsoever or any other emotion or experience that arises. 

This meditation is a training for the heart and the mind. It will build kindness, compassion, self-love and care for self and others. And you will learn a lot along the way about the mind, body and heart interaction and the nature of what it is to be human.