Just read this on BF3 Forums
Bryan: Thank you for contacting Origin Help. How can I assist you?
you: sir, I cant activate my game.
you: I've been trying for hours
you: It says that my account isnt activated and when I try to activate It goes to a 'infinite' activating mode
Bryan: I know you must be very frustrated with this.It is an issue that started creeping up on us earlier today and we have staff working on the activation server as we speak.
you: ohh so I'm not the only one, good to know. Well, any ideas when this would be fixed?
Bryan: We're hoping by the end of the day but more realistically it could take up to 2 or 3 business days to complete. However please try every so often until that time has passed and if it is unresolved by the end of that period let us know immediately.