I was eating chinese food and I had soy sauce on my rice and my 5lb yorkie got into my plate. Now she is really dragging like she is really tired.
Soy sauce is very high in sodium, and your chinese food could have contained MSG (monosodium glutamate), which is also high in sodium and can cause adverse physical reactions in humans. Since your dog is only 5lbs., it would depend on how much she actually ate, and the food could have contained oil, seasonings, onion and garlic, which can cause anemia in dogs, but if you notice her acting really tired, I'd recommend a vet visit, right now, to have her evaluated in person, and then treated.
I hope she'll be fine!