a crush is just that - you know you are infatuated, but eventually it will be crushed by someone or something, and you will move on and live.
love/being in love - means a whole lot more, you can't stop thinking about that person, even when you're not around them, you bring them up in all your conversations, if you werent holding onto something you would float away, you wake up thinking about them, just like you went to bed thinking of them. . . you can't picture your life without them.