Dog ate chocolate?

I have a 24 pound beagle that ate about 3 ounces of betty crocker hershey creamy chocolate icing about 2 hours ago. (Thank you to my husband for leaving CHOCOLATE where the dog can get it!!!) She has vomited 3 times and it has been a liquidy slimey chocolate vomit. She is whining a little and wanders around, then goes and lays down, then whines and wonders some more. I called the Animal Hospital, but they said it probably wasn't enough to worry about and to watch her, but I'm worried anyway. Her belly looks a little bloated to me too. What else should I watch for or should I be doing something for her? She's crying quite a bit...