Are you still sick? It is a week now. What you eat later wouldn’t matter, except to say eating or drinking might cause you to throw up again, because you have food in your stomach. Are you throwing up for a week now, or is it diarrhea? Or, just you feel queasy and uncomfortable? Did anyone else in the house get sick? If you are throwing up for over a week where you can’t keep anything down I would go to a gastroenterologist or another GP if your GP is not doing more tests or not trying some sort of treatment to help. It might not be food poisoning, you might have assumed that, but it might be a coincidence.
We just got through stomach flu season (norovirus usually) which usually is a 24 hour thing, 12 hours of intense horribleness praying to the toilet bowl, and then 12 hours of still feeling bad and needing more rest and hoping to hold down some food and liquid, but some people it is more severe and they feel unwell for a good 4 days.
If you have unrelenting diarrhea for a week now, that might be Camplobacter, and Cipro works great for it, and there are some other antibiotics that work well too. I think with E.coli the body can clear the bacteria and still the toxins are still wreaking havoc for a while, so I am not sure if antibiotics work as well if you wait, I am not sure. You might want to google that.