So, your whole population of nuggets got depression. Let's talk about that.
Depression in The Universim
It happens to the best of us, you're freshly starting a new village, a short while after, a nugget dies of old age (or other causes if you're not a good God). Then another one dies. Then another. Eventually, you realize that dying isn't good for your nuggets' health, both for the deceased and the not-so-deceased ones watching their loved ones fall to the ground with a bunch of flies over their heads. A dead nugget on the ground is not good for the happiness of the family members, specifically when they're just lying on the floor with an incredibly slow cemetary to pick them up eventually (or even no cemetary at all). At this point, the dreaded wave of depression begins. If this hasn't happened to you yet, good job! You're clearly doing something right, after all! Why are you reading this then? Go have a cup o' joe to commemorate yourself on this lustrous day. If you're not into reading, you might wanna pass on this one. For the rest of you, let's get right into the news.
Depression Matters in The Universim
The reason mass-depression is such a common yet devastating issue, is because it's incredibly easy to get sucked into it. One nugget dies, the family gets a hit to their joy. When nuggets get more and more depressed, they just stop reproducing, as well as the other side effects of having reduced or completely halted their work, and slow move speed. This leads to less productivity overall, and your whole village/tribe/town is basically doomed to all die of old age with no children to take their place, unless you do something about it.
How to Avoid the Issue
If you're one of them lucky buggers who never got that cycle of depression in their village, I still don't know why you're here, but maybe this part might sound familiar (or maybe not, who knows). The #1 key factor to avoiding the whole problem in the first place (at least as a temporary solution), is to not let your nuggets in the beginning die from thirst or starvation. Letting them die will kickstart a wave of depression early if you have ~10 nuggets, and of course it has its more obvious effect of reducing your workforce by 10%. Unfortunately you can't save a nugget from the disease known as aging, which is much more worrying when you have 2-3 nuggets die around the same time from old age, which can also be what kickstarts the depression wave over your whole population. If you're at this point in your game, there is almost no way to stop it, unless you already had prior preventative measures. Speaking of preventative measures...
How to Fix Their Depression
This one's gonna stay short, as it doesn't need much explaining. If you follow a nugget who's low on happiness for long enough, you'll notice that they occasionally stop whatever they're doing to take a ball out of god knows where (but you're a god so you should know) and throw it in the air, increasing their happiness. This only works for so long, as eventually all it does is slow down their decreasing happiness. In order to really get their happiness back up at this point, you need to have researched recreation. However, as the lord and saviors at Crytivo haven't quite yet gotten it right, recreation is just slightly too far away to research before the depression hits the population. For this reason, you wanna skip over a lot of research for the sole purpose of researching recreation. Once you've got that down, I recommend 1 business/recreational building per 10 nuggets in your population.