First, look at your inventory. Usually you buy food, that gives energy. It is stored in your inventory.
Second, try a restart.
Third, don’t buy food for gems. 😉 That‘s a personal advice only. It‘s absolutely not worth it.
Better spend gems on shop events or camp equipment to enhance your camp.
If it’s not in your inventory and a restart doesn’t fix it, contact pixel support after the holidays.
https://forum.pixelfederation.com/diggysadventure/d/190728-how-to-contact-pixel-support
https://forum.pixelfederation.com/diggysadventure/d/192597-announcement-support-availability-december-24-26
Edit: P.S. Next time please have a look at the thread you are posting in. If it’s about a completely different issue, please don’t post there but open an extra discussion.