when he coughs up the blood it looks like hes coughing up his insides. im taking him to the vet in the morning but i wanna know what im up againts.

My dog has his worm shots and everything, but whenever I walk him around my neighborhood he always eats random things and dog/cat poop! I’m afraid he might have worms….
How can I tell?
and what will happen?
and can humans get worms? what would happen to them?

also, a web site I can refer to would also be helpful, although not necessary.
thanks!