The dark ages were indeed a generally bad time in Europe, but much of it was politically induced, rather than climatically or epidemically induced (but I am NOT discounting that the black death (in its many waves of occurrence) were not devastating!!). Feudal lords and ladies wanted their privileges, even when the serfs died of starvation and plague, which lead to unnecessarily increased levels of suck for basically everyone. (If they had instead not focused on trying to squeeze blood out of turnips and trying to wage war on each other, and focused on keeping their countries alive through better distribution of raw materials, food rationing, the planting of alternative crops (like buckwheat, which has a short but vigorous growing season and is tolerant of cool) etc-- a good deal of the suck would have been mitigated.)
Then the church's position that it was a divine retribution for a great sin, coupled with witch hunting hysteria (and healers were often accused of witchcraft) did little to help matters.
Mostly, it is called the dark ages because of the rampant illiteracy, and low quality records that were kept. What we DO know is that for the period in question (400 to 500 years worth of time), several plagues hit, there was agricultural failure, inter-kingdom strife, and the church had a raging hard-on for power-tripping. Physical records in the forms of tree ring data suggests colder, drier temperature averages.
* Teneb puts on his medievalist hat
A "Dark Age" is any period in history of which we have very little records. It's "Dark" because we got way less of an idea as to what was going on than for other parts of our history. The medieval dark age, which is what people usually think of when they talk about the subject, went from roughly the 500s to the 900s.
Now with that out of the way, I need to clear out some things. First: it was actually not that sucky at all. Feudalism was still forming, so the number of nobles going on power trips was actually... really low. It was, in fact, probably the best period in history ever to be a peasant. Because most peasants were fucking free (less in England and northeast France). The term Villain originally meant a peasant who lived in villages and who, by definition, was free. It later got morphed into the current meaning because both nobles and burghers (meaning: city-dwelling merchant class; a Burgh is not a city, but a city's commercial district) resented that freedom. Nobles only started
really gaining power after year 1k.
Wars were also pretty brief and small in scale, likewise for plagues who can't really spread very well if the population is spread out instead of concentrated. As for the Church... it was actually pretty chill before the Schism, and for quite a while after it. Witch-hunts, for instance, are
NOT a Medieval thing, but a Modern one (I should note that english and english-derived historiography tends to merge the Modern era into the Medieval one, while french and french-based historiography does not. Brazil's own historiography is derived from the french one, so that's what I'm operating from), starting around the rise of Protestantism, which makes sense since most witch-hunts were organized by the protestants (the Catholics did do it too, just not as much). The Black Death also happened near the transition from Medieval to Modern, which is something to keep in mind. Remember that most healers were also usually priests during medieval times ("You should pray three times a day and then put on this poultice").
Medieval Europe was pretty ok to live in, as far as those things go.