Belching, dull pain abdomen

[Jalopino]

Last month i had a gastrointestinal viral infection for 4 days and had to be hospitalized for 2 days because i was dehydrated. When i got out i was feeling alot better i had antibiotics, omeprazole, and loperamide for one week. After I finished my meds i went to a party and drank a lot of alchohol on a saturday night, monday came along and my stomach was still feeling fine, so i went to another party and drank alcohol. By wednesday morning my stomach was feeling really bad It was empty and i vomited green liquid. My stool suddenly changed light brown and my stomach hurts everytime i moved. Went to the doctor and told me it was acid so he prescribed me omeprazole for one week. My stomach felt a lot better but sometimes it still hurts just a dull pain but it worsens if im hungry.
Stool is sometimes hard (light brown) and sometimes watery & foamy(light brown) and right now i just pooped a really dark brown one (wet). Im 18 btw