All of your notifications can be found by clicking the bell icon, located in the upper right corner of your window. You will also be notified by a red dot upon receiving a new notification. On the mobile app, the bell icon will be located in the lower right corner of the screen.
You may filter your notifications by comments, reminds, and a number of other criteria by using any of the icons in the dropdown notifications menu.
You may also view your notifications on a separate webpage by following the link under View All Notifications