I lost just over 40 posts - there was a database roll-back which means that the whole site will have had its content moved back - and backdated a day.
Many of us will have lost content and things like the_nines has experienced will have happened - and will need to be attended to again. For things as specific as this you should PM a Mod - like Luvvinvinyl for example and explain - he will put this right for you. However those who can see that their content (posts, likes, profile updates, etc) is missing will have to accept that it is gone forever.
We apparently experienced a 'DDoS attack' (= Denial of Service) - which means that malicious servers somewhere launched an attack via the Internet which choked up communications with this site thus dramatically slowing it down, seriously disrupting normal site functioning, and corrupting databases and indexes as a result.
This is just my guess at what happened, based on a few snippets of posts I have seen from Wardsweb about the recent problems. I hope there will be an official explanation provided in due course when the dust has settled, just so we all know what happened.
To get the site back 'up and running' after such an incident is a great deal of work. To have suffered relatively little disruption, and relatively small damage is a testament to the skill and dedication of Wardsweb and the other 'behind the scenes' staff who worked so hard to repair the damage. We owe them a huge debt of thanks.