Well, the dog and I are doing much better today and the mystery of how Maddie got sick in the first place was solved last night when my husband discovered her eating from the garbage (a banana peel to be specific).
Our Maddie is a sneaky creature, so we don't even keep our garbage in the kitchen anymore. We keep it in the office where we can close the door and completely deny her access to it. Unfortunately, my husband is absentminded and has been forgetting to close the door, which resulted in a mischievous dog sneaking bites of garbage. Ugh. So, now I've been careful to close doors after my distracted husband and keeping a close eye on my mischievous dog. A mom's work is never done.