Hi, so sorry you're going through this with Lear. I was going to suggest to you that she may have eaten something that you didn't know about, and since you mentioned that you found a piece of plastic in her poop, I think that's what is causing her to have diarrhea and vomiting. These are both signs of an obstruction, or of having swallowed a foreign object. My English Bulldog Dozer has swallowed sweat socks twice, and both times he had the same symptoms, he started with diarrhea, then vomiting, he drooled water from his mouth. He ate and drank like normal, and had normal poops as well, but then after the symptoms started, he became lethargic. We brought him to the vet, and Shelley his stomach and could feel a mass in there, she took an X-ray which showed a shadow of something in his Intestines. She gave him IV fluids, pain medications, and a laxative. She sent us home with a fibre prescription dog food, which we fed him a Tbsp once every two hours, and he was able to pass the sock that evening. We didn't know he had eaten a sock, and it could have been there for a week or more. It takes time for them to pass items out, and most of the time they are able to do so, but you have to keep an eye on her and watch and check every pop to make sure they do pass it. If they can't, or they continue to be sick, sometimes surgery is necessary to remove the foreign object. I hope Lear is able to pass the rest on her own, and I hope she feels better soon. Sending love, hugs and prayers your way. Please keep us posted on how she's doing.