After Mojave installation all my passwords are gone

Hi there, Grhoades2448!
Thanks for reaching out to the Apple Support Communities! It sounds like you’re having an issue with your passwords not being restored from Keychain and I’m happy to help! I suggest starting but checking out this article to Get help with iCloud Keychain if you use iCloud for your access to keychain across your devices.. Specifically:

If you don't see your iCloud Keychain items

There are several possible reasons for why you can't find your iCloud Keychain information:

• Did you restore from an iCloud backup and then notice missing iCloud Keychain items? iCloud Keychain items aren't part of iCloud Backup because they already live in the cloud. To find your iCloud Keychain items in iOS 10.3 or later, tap Settings > [your name] > iCloud > Keychain and turn on iCloud Keychain. For iOS 10.2 or earlier, tap Settings > iCloud > Keychain and turn on iCloud Keychain.
• Did you turn off iCloud Keychain on all your devices? If so, your iCloud Keychain is removed from the cloud. If you chose to delete the keychain items from your devices when you turned off iCloud Keychain, your iCloud Keychain is also removed from those devices. You need to set up iCloud Keychain and add items again. (If you turn off iCloud Keychain on all your devices and choose to delete your iCloud Keychain locally on all your devices, Apple can't recover your iCloud Keychain.)
• On your Mac, did you use Keychain Access to reset your iCloud Keychain? If so, macOS deleted your iCloud Keychain items. Try setting up iCloud Keychain again. If you need to reset your Mac Keychain again, temporarily disable iCloud Keychain in iCloud Preferences before you reset your macOS Keychain.