I would say the new food perhaps doesn't agree with her or the probiotic if that is new might also be the issue.
I would let her rest and try making her next meal only the old food and see if that resolves the problem.
If the new food is higher in fat some dogs don't do well with that. Same with certain grains or protein sources not being easy for some dogs to adapt to.
Once she feels better then try the old food in combination with the probiotic and see if that triggers vomiting again. If she always has the probiotic I'd not bother with that. I'd strongly suspect the new food as the issue if its not the probiotic.
If she gets worse, can't eat or drink without vomiting etc then you should see your vet but for now waiting and rethinking your food changes should be OK.
Hope this helps you!

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