Have you ever loved something so much, that you couldn't stop thinking about it no matter what? Have you ever saw something at the store that you wanted so badly, you did everything you could to get it? This is like the same thing with God! We want Him so badly in our lives all the time whether it's a bad time or a good time.
The love of God can have many definitions. It could mean The Love for God or The Love by God. The Greek terms for love are theopilia, which means the love or favor of God, and theophilo which means friend of God, originating as and still in the sense of being loved by God. The term agape is another Greek word for love. It stands for the human love we have for God and the human love God has for man.
As well as love having definitions, it also has many attributes that attain to itself. It's caring. His love won't fail you when the world fails you. It's eternal. It doesn't have an end to it. There is a full never ending extent to His Wonderful Love.
Next time when you are feeling down and unloved, just remember that simply put, God Is Love.