My pet vomited today and it felt very tired and ...

you asked what should i give my pet to make it vomit? vomiting  makes  anyone, including  animals to become  dehydrated..     if the person or animal is extremely dehydrated then  heart attack can  follow. instead of looking online for  answers    for your animals  you need to get it to a proper source. A VETERINARIAN

Make sure their is always fresh water and food available. Dogs and cats throw up. Sometimes they eat a leaf from a plant, something in the yard and it doesn't agree with them. Keep a close watch.

Did it throw up any grass?  Usually when their bellies don't feel well, they eat grass.  So don't ever stop them from eating grass (unless, of course, it's just been poisoned by grass/bug people).

Is it a puppy or adult? Really don't make too much difference, they are a lot like humans, they have their off days. One thing, if you think he had something wrong with him before he vomited, take him to the vet. If he was playing and happy before then, let it go outsde and eat some grass, or maybe it ate some when it was out earlier. Dogs will seek out the right grass to nibble on when they have a queasy stomach. Then they might vomit some, but not a whole lot, and they will be slow to move for hours but they usually spring back fast.If it continues, please take it to the vet.

Um ya! You need to contact a Vet or take it there!

all animals (inluding humans vomit on occasion and usually doesn't mean much. but this sound serious.  go to a vet.

Maybe it had eaten something that caused its stomach to rumble, it is much better if you take it to the vet to have some checkup. In Canada Pet Meds thy are giving out some advice on what pet owners do in such situations like this