Sent emails are here: Outbound > Sent Messages.
If you can't find your sent message here, try clearing the checkbox Hide Messages to Specific People (top left):
'Messages to specific people' are emails that were not sent to any lists or segments, only specifically selected contacts.
Other tools to find your sent message:
- Text search at the top left.
- Folders in the left menu.
- Sort at the top right.
Related to