Gastritis???????????

I have been feeling sick most of the time since the start of the month. I have been to the doctors 4 times and had a blood test which showed I had a swollen gall bladder but everything else was ok. Told to go back for a further to test to see if it goes down in a few weeks. Doctors told me I have gastritis based on my symptons (nausea/vomiting) and prescribed Omeprazole (10mg) one a day. No endoscy examination though. Problem is this was 10 days ago and I dont feel better. Been sick several times today after drinking plain mineral water and on sunday night I suddenly became really exhausted and felt very nauseas all through the night and into monday. Went back to doctors monday morning and was told I had gastro enteritis on top of gastritis ????? I dont seem to be getting better and as I type feel sick. The doctor on monday said my blood test showed I was slightly jaundiced !!! I am starting to really worry something is seriously wrong with me. Does gastritis sound right anyone ?