There are different ways to to look at your Notifications:
When you click on the Bell icon, wait for the posts to load and then click on the grey text 'Google+ notifications', you get the all notifications stream view; there are different ways to view your mentions and comments.
Check the top of the page and see more choices:
- Your posts (Other people have commented, +1:d or shared)
- Other people's posts (posts with your own comments or posts that others have directly shared with you, also posts from any Notifications / Subscription circles)