My 28 month old daughter has been vomiting and has diarrhea for the last 24 days. I have taken her to her pediatrician, an allergist and to the E.R. and all I keep hearing is it's okay, she probably just has a virus. She is not running a fever. She has lost weight. A stool culture was done, and it was negative for bacteria and parasites. She is allergic to eggs. I have a really loud voice in my head and feeling in my gut that there is really something wrong and I just can't get anyone to take me seriously. I just don't know what to do. Any advice?

My 28 month old daughter has been vomiting and has diarrhea for the last 24 days. I have taken her to her pediatrician, an allergist and to the E.R. and all I keep hearing is it's okay, she probably just has a virus. She is not running a fever. She has lost weight. A stool culture was done, and it was negative for bacteria and parasites. She is allergic to eggs. I have a really loud voice in my head and feeling in my gut that there is really something wrong and I just can't get anyone to take me seriously. I just don't know what to do. Any advice?

I don't know but would try another allergist for another food allergy (she's not eating any store bought foods at all during this? Sorry, I am sure you check labels very carefully).
You could probably safely do a diet of a very few foods for a while to try finding an allergy yourself. No wheat or dairy, no packaged foods, just oatmeal and rice and vegetables. Minimal protein, tiny bit of no hormone no antibiotic steamed chicken.

.. no butter, but some oil is needed, about 2 T day, olive or canola.

Oops, crossed in the mail.
Dried fruit preserved with sulfides?

I remember Adele Davis' book Eating Right to Keep Fit (?) starts with a story about a toddler who is not doing well and it was lack of a little oil in the diet.
As for viruses: I once had a virus that gave me chronic diarrhea that wouldn't go away, and I was told I had to stop eating for 3 days, so I did and it went away. Intestinal viruses thrive on food. Water only.
Good luck I know there are so many possibilities.

Go back to the doctors,go back to your gp,keep asking the questions.

I would urge you not to try any drastic diet changes on your own.

My fear for your daughter would be dehydration,keep bringing her to the ER,doctor,nurse.

Keep on their case until they get to the bottom of this.

You might see if you can get a referral to a pediatric internist.