My 4 year old woke up Tuesday morning vomiting with a fever. Throughout the day she continuously complained of pain in her lower right abdomen but my husband said that it would be worse if it was her appendix. By 7pm she was vomiting bloody foam so I took her to the urgent care where they advised I take her to the pediatric ER at the hospital. I took her in and they said it was most likely the flu but they were going to do a CT just to be sure. Well her appendix was huge so they rushed her into emergency surgery at which time they found that her appendix was on the verge of rupturing and her abdomen was filled with infection. They kept her 1 day then sent us home with really no instruction. Today (4 days later) she still has a fever (99's) and her belly is still rock hard and tender. She has yet to pass gas. Should I be concerned?