Cant keep nothing down what to do ?

i had an emergency appendectomy dec. 2nd, no complications, a week after getting discharged i was back in the ER with chest pain and trouble breathing was then diagnosed with pneumonia and was given an antibiotic for 5 days. my problem now i ever since surgery i have been very nauseated and usually within like 20 mins of eating i vomit it back up i have talked to my doctor and he said to give it time. but i dont think this is normal i am losing weight i went to see him last week and i told him i was not feeling better at all and all he said was give it time and come back in a month... what are some good things you can do to try and keep food down ? ive tried sports drinks, ginger ale, and bland food nothing is staying down... im keeping a little bit of my food down but not much. what should i do my doctor dosent seem to be to concerned.. should i be ? i have had 3 previous abdominal surgeries in the past 2 years and have never delt with this before. and i dont want to go to the ER because it cost to much and they never take me seriously and truly all they can do is give me fluid and nausea meds and send me home.