Ellie just vomited for the first time in her life and the vomit has little pieces of black plastic in it. I have looked all over the house and all over the yard and I can't locate anything with black plastic. If she just threw up now, could it possibly be something she ate at the dog park yesterday late afternoon? She also has had diarrhea the last two days. I am wondering at what point should she see a vet? With all the health related incidents she has had, this kind of thing just scares me probably way more than it should.