Yes isolation is NOT a natural state for humans who are gregarious social creatures. Lonesomeness is widespread in western society, with a large proportions (1/3) of households being a single person. 20% of seniors live in relative social isolation.
Without some social acceptance, without some success amongst peers, without a kind person, without someone who loves you dearly, a person is vulnerable to growing self doubts and preoccupation with the worries of life.
Given that life itself is a bully, many isolated persons are amongst those who have griefs to revisit when alone too long. In the end one has to get out there even once a fortnight to a club of like minds, and force oneself to get outdoors and active a few times per week.
It takes a while to be discovered by charitable welfare groups and people have died in their houses and not found for 12 months or more.. so get some peer or care situation that expects to see you regularly.
The bottom line, the base social need of all people is to be taken seriously (Hugh Mackay- what makes us tick)
Most people who are lonely enough to get depressed are very wary of who is truly kind, and who are "users".
It does, for people who are used to being in a large group of friends, the centre of attention kinda guy. Or people who need someone to lean on for support when they're in trouble or sad. But for people who are used to it, yep. We find happiness in solitude.