Haroula, it will be from the vaccinations she's just had. The Rota Virus vacc can really knock them for 6 when they have it - Alister took a full 2wks before he was completely back to normal. he wouldn't have proper, full feeds and was all over the place with it. Persevere with what you are using, she will start to improve again in the next few days.

Which formula did you settle on? Try giving her a little rest and then see if she will have the rest of the bottle.