If you spend a long time writing a post and then press the Post button you will have timed out of your session and be presented with the login screen. At this point most people believe they have lost their post and chose to feel 'upset'. You have not lost your post. Log in as required and then use your browsers 'Back' button to go back a couple of screens and there, in all its creative and virginal glory, you will see, your post.
All you have to do is press 'Post' again. Now that you are logged in it will work this time.
Rick Bateman
Founder
Social Circles Canada - A New Kind Of Health Club
socialcirlces.ca
+48° 25' 43.45", -123° 20' 10.20" (hint: Google Maps)