If you are not feeling well over 2,500m.it may be Acute Mountain Sickness (AMS) until proven otherwise.
EARLY SUMPTOMS
* Headache
* Loss of Appetite
* Dizziness
* Fatigue on the Minimal Exertion
WHAT TO DO ?
* Don't go higher, rest, drink fluids (not Alcohol)
* Symptoms go away=go up
* Symptoms get worse=go down
WORSENING SYMPTOMS
* Severe Headache
* Vomiting
* Walking like a drunk
* Increasing tiredness
* Shortness of breath at rest
WHAT TO DO ?
Descend! Descend! Descend!
Don't let anyone with AMS symptoms descends alone.