My baby girl will not eat much. When she walks she stumbles. She sleeps all day. I took her to the vet they tested her for a particular parasite and it was negative. But they gave her medicine for worms and other parasite. Does anyone have and ideal of what this might be. I low income and can't afford constant vet bills. I don't won't her to die?

Does she continue to stumble after she eats or is it when she goes a while between meals?
Has there been any vomiting or diarrhea? Has she had her vaccines?

There's very little advice we can give. We can't diagnose online, and it seems that even your vet is having a hard time figuring out what's wrong.

The symptoms she's having could be many different things. What other tests did the vet do?

For now, give her the medication. If she doesn't start doing better in a day or two, you will need to go back to the vet. Sadly that's part of owning a dog, and it can get expensive. But that's what you agreed to when you got her.

I'm sorry, I wish that you could find the answer online, but it simply isn't possible.

The reason for my questions was this.
IF the problem is not eating very much and lethargic, then you may have a puppy who's blood sugar has dropped, it will make them weak, sleepy and wobbly, this is not that unusual for chihuahua puppies. It's not a good situation but in a pinch you can give a small amount of syrup or rub it on her gums. If that perks her up then low blood sugar may be the culprit.
Get her to the vet and request that they check her glucose level.
If she is having vomiting and diarrhea then that changes the whole ball game.
There could be many things going on, but nutrition and warmth are very important when it comes to puppies this tiny.

Oops! You must spread some Reputation around before giving it to LadySam again.

I agree with Lady Sam. Didn't see her first post when I posted. We posted within a minute of each other.

Bottom line, you can try different things, but ultimately you're going to have to have your vet involved in figuring out what's wrong, if it can be treated, and what treatment is needed.

If you're on a fixed income, which I completely understand, talk to your vet. Many vets will set up a payment plan if your animal is sick and needs treatment.

Does she continue to stumble after she eats or is it when she goes a while between meals?
Has there been any vomiting or diarrhea? Has she had her vaccines?

Yes she was vomiting before I took her to the vet. Now she just lay around and sleep she has a brother but he is not sick. She stumble after getting up and she will it very little once a day. I'm going to contact the vet again.

Possibly low blood sugar. Very common in the small/petite breeds.. try rubbing Caro syrup on her gums.