[Koliakis]

No social contacts with friends or strangers who could become friends (or even a partner). So loneliness and lack of intimacy. The latter is a killer.

[throwaway45349]

For sure, this is a big reason. I'll be 21 when this is over, this year of youth is never coming back.

[nitrogen]

In hindsight your early 20s are a lot more fungible than it seems at the start. 20-25 you can really do a lot of the same things. Heck, even your 30s you can do a lot more than you think you can when you're looking forward from 20.

Also keep in mind that everyone your age is in the same boat this year.