A deep, often depressing, feeling of wanting to find
love; to be loning for
love; to be without a companion to share ones life with, though it is desired deeply.
(Don't believe the other definition that has all those thumbs up for saying it is being in
love and "drawing hearts in the sand" and stuff, becauase that is the opposite, that is lovestruck, not lovesick).
Lovesick is like homesick.
Homesick
people are away from home but want to be home.
Lovesick people are away from
love and want to be in
love.