I have a 7 week old chihuahua that has had the 6 week old shot and now will not eat or drink all it will do is sleep no energy at all. What do I do?

It sounds like she is having a reaction to the vaccine. Have you called your vet? Is she drinking? How long has she not been eating for?

It is common for them to feel a little lethargic for roughly 24 hours, it's much like a flu shot for humans.