Google Security Alert (non-private connection)

Hi,
I logged onto my wp-admin dashboard, normal.
Then I went to the Wordfence dash, it had 2 notifications so I clicked on the notifications link.
Then a Google Security Warning (red warning in URL bar) came up saying it’s not a private connection and I shouldn’t follow the link. Didn’t follow the link.
And now when I log into my wp-admin dash (password stored in browser) I get a ‘cookie disabled’ warning (which is nonsense! cookies have not been disabled!) and when I click on login again without changing anything it logs into the wp-admin dash.
Then I seem to get logged out of wp-admin automatically within a few seconds and the wp-admin login screen comes up again with no password auto-inserted!
Very strange! And everything was normal yesterday on the site http://www.walksforyou.com
Very suspicious!
Any insights at all appreciated, thanks!