The hell is this?

So I log into my g-mail account and I get a screen that says that they've discovered unusual activity on my account. In order to verify my account the page wants me to enter my mobile phone number into the site, and it claims that they'll SMS me a code to get into my account.

This is ridiculous on so many levels. If someone has hijacked my account wouldn't it stand to reason that they might find that stupid screen first? Google doesn't know my cellphone number, so the account would be up for grabs then I guess? I don't own a cellphone, and cant receive a text message. This does not sound like a security option that a reasonably informed company would make, and google is quite smart. Even so Google is based in the Northern California technocracy, and the assumption that all persons who use e-mail also have the ability to send and receive text messages via a cellphone seems like the sort of elitist foolishness that might come from a person there.

All together I believe that the page is inauthentic, which leads me to wonder has all of google been hacked, or have I or what. On who's end is this mischief? Is a DNS server close to me compromised, is google compromised, is my very computer compromised? Is a security measure an actual paid human being who likely presents themselves as an expert in some field really came up with?

Please do respond. However I'll never see the responces if I don't get e-mail notification of them.

Well.

Well I gave the apparently authentic Google page my phone number, and they called me with an automated voice giving me a code to unlock my g-mail account. Changed my password. In my account is record of eight spam mails sent from my account, none of which reached their recipients, they all bounced. I hope that's all that was sent! If you've got a spam mail from me let me know so I can panic about my e-mail account sending my grandmother porn links or something.