If you're playing DST, you should be able to revert your own servers to an earlier state. This can be done in the "Host Game" menu under "Rollback" after selecting the specific game. You should be able to go back 4 to 5 days there. Be careful, once you reset your server, all progress you made from that day on is forever lost!
If you're in single player, I don't think there's a way to go back.
Please do not spam users' message walls asking the same question, starting one thread should be sufficient. I may also recommend taking a look at the official forums http://forums.kleientertainment.com/ if you experience further trouble. :)
I have never used it, so I am not entirely sure how it works, but there's "c_rollback(count)", where "count" is the number of saves you want to go back.
Servers usually auto-save each day just after night ends, but it probably also depends on how many times the server was shut down and launched during this time? Sorry, I can't say for sure.