To find out which teams and Office 365 Groups you belong to, click on the following link and enter your credentials when prompted:
https://account.activedirectory.windowsazure.com/r#/groups
You should see the following screen:
If you see a message "This functionality is not enabled or not available," click on Reload button in your browser.
If you see the list of apps instead of the list of groups, click on your picture in the upper right corner and select Groups fror the menu.