It could be one of two things:
1.) They are making changes on the back end at the moment which might be causing some issues. This was public that they were coming, mostly related to photos but it's a bet that the code is being changed through the software that relates to how photos are handled.
2.) This is just pure speculation here but Anonymous has been going after sites that have hosted, do host, ISIS content so they might be making a run at FB. I haven't looked into though because I honestly don't have much of an interest.

1 sounds highly plausible.
2 I don't think they would go after the whole site, since the site is helpful in other ways. Plus I would think they would target specific pages, but this is only speculation.

Thank you for the comment.

It's working fine on my side.