Im a vegatarian but im craving meat!!! How do i stop craving!?!?!?

Every day i come home from school, go to the bathroom, change my clothes, then walk downstairs to get something to eat. But every day(every day my dad works nights that is) when i walk downstairs my dad is sitting on the couch eating a big steak and it always looks so good and smells so good! I think meat is disgusting and repulsive but its smells so tasty and juicy and delicious!!! I want it so bad, i resist but I'm gonna crack one day, and i don't want to!! How can i stop!!?!?!?!?! I know its gross and bad and bad for those poor animals who die for fatty, -heads who only care to get their slaughtered, dead, disgusting, meat, and i don't want to be one of those -heads!!!! I want to be a clean(clean as in intestine clean...and bodily clean too i guess), healthy, vegetarian. But it smells sooooooo good. HELP ME!!! How do i stop the cravings?!?!?!?!!?