My Pug Puppy Has Thick Green Mucus Stool, At First It Was Liquid Now Its Thicker And He Just Keeps Pooping It Out?

It is a good thing that your dog is still eating, drinking, and has normal amounts of energy.  However there is nothing you can do to stop the diarrhea at home.  This could be from dietary indiscretion, intestinal parasites, bacterial overgrowth, food change, or stress.  Your dog needs to be examined by a veterinarian, have a fecal sample tested for intestinal parasites and bacterial overgrowth.  Then appropriate medication can be started.  
Start feeding a bland diet (boiled chicken, boiled rice), canned pumpkin, and plain yogurt for 3-4 days to help settle the stomach.  With diarrhea this bad the bland diet alone will not resolve it.

It could be because you give him leftover's some dog's stomachs don't respond good to that try giving him dog food and if that is what you give him I am not so sure what could be wrong there maybe lot's of flys step on his food or any kind of bacteria could be in it.

It could be an Infection, it could be a blockage, it could be anything. The green poop can indicate that your dog ate something toxic, the blood in the stool can indicate a blockage. We cannot diagnose your dog over the Internet. We would only be guessing the problem and that will not help your Chihuahua any. You have to take him or her to the vet as soon as you can get her there. The sooner the better. Emergency Vets are open 24/7, so there is always's a vet available. You need to take this seriously, because the longer you wait to take him or her to the vet, the worse he or she will get and the harder it will be to treat the problem.