Nothing major, and in isolation very trivial, but a number of things seem strange.
(1)I have had no notifications, although if I click on interactions I see that I have had a like on a story.
(2)I have apparently had no visits to my page on checking Activity. Not necessarily inaccurate but a bit surprising.
(3) One message that I have sent, and I can see by clicking on messages on the person's page, does not appear in my messages.
(4) None of my sent messages today are being shown as read, in itself not necessarily unusual but along with these other things, I am wondering if everything is running as it should be.
If there is a (5) or (6) I will get back to you!
Just as an addition to (3) I have just sent a message to someone else and I can see it on message on their page but it does not appear in my messages list.