This sounds like the IBS that my children have! They produce too much stomach acid and then their stomach hurts and burns when they eat and when they don't eat! They get d* and severe n* to the point of actually v* sometimes. They are both on different types of antacids. The oldest takes Prilosec (name brand) and my son takes Previcid (name brand) They take it on an empty stomach 30 minutes before eating breakfast every morning. It has worked wonders! I too have done this on accasion but with mine comes severe heartburn so I take Nexium (name brand). If you are able to purchase these over the counter where you live, try them. The Prilosec and Previcid are both over the counter here in the US so I don't have to have a prescription for them any more. Although their Doctor gives us one so we can buy the generic form cheaper. Since starting these antacids they have had NO more problems like this! YAY!
Something that seemed to help them and myself until I found out what was wrong was cinnamon and sugar toast. The cinnamon and sugar mixture kept their sugar up in their system and the toast helped absorb the stomach acid.
I agree with Spilled_Milk, it isn't a virus you have had the pain and sickness feeling for too long. Try an antacid. Even if it is Pepto or Tums...