Hi
Thanks for asking.
I think you are suffering from a viral infection.
You seem to have multiple system presentation with
diarrhea,
vomiting, and
headaches with loss of energy.
Viral infections usually present in this way, can last up to 2-3 weeks and most of the time the symptoms are not severe as in bacterial infections.It is more of a slow grind rather a quick shot.
As you are having the symptoms for two weeks, it may not be a bad idea to get the general physical examination along with some lab.Investigations to rule out some serious pathology.
Hope it helps.