Hello @Nathan Dorr
Please find the below document links to validate your usage and check on your spend which will give you an idea where the charges might have been incurred.
Validate the usage: https://learn.microsoft.com/en-us/azure/cost-management-billing/understand/download-azure-daily-usage#download-usage-from-the-azure-portal-csv
Check spend on azure: https://learn.microsoft.com/en-us/azure/cost-management-billing/manage/check-free-service-usage
If the above doesn't help, please feel free to create Azure billing support request for further assistance:
How to create azure support ticket: https://learn.microsoft.com/en-us/azure/azure-portal/supportability/how-to-create-azure-support-request#go-to-help--support-from-the-global-header
Regards
Divya