Another way is to click on the Thread tools that is above the message on the upper right side.

But you may also need to set your email notices options in the User CP to allow them instantly , daily, weekly etc.

look for this section - Settings & Options
and then {Messaging & Notification }
[Default Thread Subscription Mode
When you post a new thread, or reply to a topic, you can choose to automatically add that thread to your list of subscribed threads, with the option to receive email notification of new replies to that thread.]

{it will have a drop down list of choices}

you can also set your display mode to show newest posts - it helps on those long threads that you might be following.

Also clicking the New Posts will bring up the new messages/threads on all forums - so that is another way to see new posts & replies.
http://neurotalk.psychcentral.com/search.php?do=getnew