How is it possible for someone to make you so happy that you

How is it possible for someone to make you so happy that you can't even explain what you are feeling? You feel like screaming and singing at the same time. The butterflies are so crazy and uncontrollable that you feel like you are going to be sick. They make you so excited that it feels like you are going to explode. Anything and everything seems to remind you of them and it seriously makes your day great. Every love song reminds you of them and every sad song makes you miss them and long for them to be there with you. Their eyes become your favorite color and their voice becomes your favorite sound. And you feel like if it means that you will be with them, you will follow them to the ends of the earth.