If she ate that much and it was all grain, you need to get a vet involved ASAP. Don't wait!! Overload is way more of a concern than bloat. Dehydration, acidosis, & founder are your main concerns right now. You'll also need some antihistamine into her system asap to help prevent foundering. You'll need to treat her for a few days here up close. Again if it wasn't all strait grain you'll have a better chance, but don't wait and see on this one. Be proactive.