What Causes Tiredness, Appetite Loss And Stomach Bloating?

my 5 year old daughter was unwell last week,she was sick a couple of times and did not want to eat anything for about 3-4 days. she has gone back to school this week but each day when she gets home she is very tired,more than normal,and is still saying she feels sick,but not actually been sick. Also her stomach is very bloated and hard Regards Mark