What is lovesick?

Lovesick means lovelorn, longing for love or missing the person you love, to the point that you don't behave normally, to the point others notice your behavior.

I believe that lovesick is a special thing. if you love someone so much that you can't act normally than you are lovesick. When you are lovesick you can't think straight, you fell like you just want to be around that person 24/7, you just feel empty without him/her, and you just don't want to do a thing until you see them again.