Logging on to see your items or Shillings have disappeared is alarming, but is usually a short-lived issue. There are 2 reasons this may have occurred:
DLC Ownership Has Not Been Recognised by Steam
The most common reason this occurs is when Steam doesn't recognise DLC ownership correctly (purchased items are considered to be DLCs, too). This means that any items or Shillings belonging to a DLC will appear to be missing.
You may notice this happens more regularly when the Steam servers are disrupted.
Rest assured, this will resolve itself. Keep restarting, and your items and/or Shillings will eventually reappear. If Steam is having problems, you may need to wait for that to pass. We recommend using the DownDetector website to check Steam's status: https://downdetector.com/status/steam/
Steam Family Sharing
If you had previously been using Steam Family Sharing to play Vermintide 2's DLCs, you may notice that option is no longer available to you and any DLC-related items (such as Bögenhafen weapon illusions) or Shillings have disappeared from your inventory.
These items have not been removed from your account or un-applied from your weapons, however, to use them again you will need to own the relevant DLC yourself.