hey,how are u,my 6 year old little girl has had a fever for 3 days,its goes upto 104 but then comes down with calpol ,she is very weak but drinking 7up,she has started vomiting but its not sick its thick balck liquid,a lot of it could u please tell me what this could be,its not the usual lining of the stomach ,its much thicker and darker and theres no sick in it,just this liquid