Someone may have accessed your account (Facebook)

I have a Facebook account. I log in a couple of times a year. Yesterday I have got an email from Facebookmail with the subject "Someone may have accessed your account". I have clicked on the link and tried to "secure my account". But after first click and than "continue" on the Facebook I get a feedback like this: "An error occurred while processing this request. Please try again later."

1. Is my account really hacked?
2. What should I do?

The email from Facebook? (security@facebookmail)

Hi,

It looks like someone may have accessed your Facebook account. To secure your account, you'll need to answer a few questions and change your password the next time you go to Facebook.

For your protection, no one can see you on Facebook until you secure your account.

Thanks,
The Facebook Security Team

After my click on the link in email I see this message:

Someone May Have Logged Into Your Account

In order to keep your information secure, we've locked your account. Before we can unlock it, please verify your identity and change your password.

Your account will remain hidden until you complete this process.

And when I click on continue I see this one:

Sorry, this feature isn't available right now

An error occurred while processing this request. Please try again later.