I'm here to help you fix the issue in creating an invoice, @markbutler37.
 
Product /Service not showing when creating an invoice is an unusual behavior. It can be because of a browser issue.
 
I recommend logging in private browser and try to create an invoice. See the keyboard shortcuts keys below:
 
 - Google Chrome, press CTRL+ Shift+N
- Mozilla Firefox: press CTRL+Shift+P
- Internet Explorer: Press CTRL+Shift+P
- Safari: press Command+Shift+N
 
If it works, you can start clearing your browser's cache to ensure it functions properly. If private browsing does not work, switch to another supported web browser for the best and most secure QuickBooks experience.
 
Lastly, here is an article for future reference in reconciling your account: Reconcile an account in QuickBooks Online.
 
Let me know if you have question about managing invoices in QuickBooks Online. I'm always here to help. Have a great day.