Didnt get gems only lost all gold.
Try exiting the game completely, and then logging back in. Sometimes that can “fix” the display error.
Edit: Looks like this is a bug affecting several people. According to this thread, most of them just had to wait a few minutes for things to appear back to normal again. https://forum-en.gw2archive.eu/forum/support/support/Missing-Gems-5/first#post6533754
skritt stole them whilst you weren’t looking, better luck next time.
thx got gems