Don't worry, everyone still loves you and nobody has intentionally blocked you. The problem is that a large chunk of your friend/fan list can't see anything you post and here's why:
Facebook has a news feed setting that by default is automatically set to show ONLY posts from people who you've recently interacted with or interacted the most with (which would be limited to the couple of weeks just before people started switching to the new Facebook profile).
So in other words, for both business and personal pages, unless your friends/fans commented on one of your posts within those few weeks or vice versa - you are now invisible to them and they are invisible to you!!
HERE'S THE FIX: On the homepage click the "Most Recent" title on the right of the News feed, then click on the drop down arrow beside it and select "Edit Options", click on "Show Posts From" and change the setting to "All Of Your Friends and Pages" (you can also access the "Edit Options" link at the very bottom of the Facebook homepage on the right)
This is a re-post from Anne Bradshaw. Check out her blog here.