In Search of This Really Cheezy Gore Horror Monster Flick?

For years and years I have been searching and searching for this really gory monster movie about this old woman who barfs up this bloody slug thing. Then the slug thing goes into her son's room and crawls into his body through his mouths while he is sleeping. Then a little later he barfs up the slug thing and keeps it in his bed. The slug thing forces the boy to go out and kill people to feed it fleshes and blood. The slug thing gets bigger and bigger and has these really big tooths and it eats people and gives birth to more slug things that grow and grow and take over the kid's house as he keeps feeding them more and more people.