I'll give it a go in a mo if I have lost my saved info again. I think I have an idea of what the issue is. Is the character info linked to a specific server, albeit, the information saved locally? if so, I wonder if the issue is realised to that when I open the game, as it is unable to find the server straight away, it resets to default 'survivor'?
The Official server were down today for maintenance ( I only found out after someone copied a screen shot of Twitter into a thread on here, I don't use Twitter) and I wonder if because the servers were down, my character was unable to load due to no linked server being available? Could this be the reason why I lost the last character?