Our hunter gatherer ancestors didn’t take Prozac.
Of course, we’ve no way of knowing whether they might in theory have needed it.
Who knows, they could even have consumed their own naturally occurring mood-lifters in the form of certain plants, but it seems likely that they would probably have lived a life in which their emotions were driven by external factors such as whether or not they had food and safe shelter.
In such circumstances, I suspect you’d accept your lot, and would go with the flow.
With no healthcare system, physical illness might well be fatal, but in general I guess that tribe members would be reasonably fit, eating frugally (no super-sized meals) and benefiting from plenty of exercise.
No going on diets for them, nor gym memberships.
Hovever, it’s very different for us of course.
In the 21st century developed world there’s no real shortage of food, and we can often go through a day without getting much ‘mandatory’ exercise: we don’t have to walk for water or battle marauding enemies.
Instead, annoying as it is, we must take care of our bodies rather than expecting that they will take care of themselves.
The way you feel can be strongly affected by what you eat and drink, and the amount of exercise you get, so try to keep this in mind as the day progresses.
Wherever possible, choose healthy food options.
Drink your fair share of water.
And aim to up the amount of exercise you get, even if it’s only walking up one more staircase than normal.
Or, of course, you could always move to the Serengeti.