I think there's something wrong with my dog, please help!?

We've been gone for 2 days and left her in the care of a good friend and she had a daily routine like this; She was taken out and fed (presumably) then left outside for a couple hours until our friend came to check on them at twelve, then he left and came again at 6 to put them inside. When i came home there was a full bowl, which means that either he over fed her wayy too much or that she didnt eat, I took her inside when i came home and she went on my bed and sat down. A couple seconds later she got up and sat again somewhere else. Then as i was folding clothes i realized tha her stomach was receeding and she would whimper a little. PLEASE HEPLP! i tried calling the friend to ask him if she ate anything. is she just hungry? or did she eat something bad?? please help now!!