All my pages titles are now missing (Expt Home)

Hi, All the titles on my site just suddenly disappeared when I was editing the settings to Appointments+. I was typing a post about an email bug I found and then noticed the title tags in all the pages on my site do not have text in them. They were not like that a few minutes ago.
Example URL:
http://accountproductions.com/about-us/
I am really unsure what happened.