I wanted to Sign In as I do regularly, but when I clicked Sign In, I first saw a page about some problems that had appeared before (because of which I had been logged out). I decided to Sign In with Google Account this time. So I clicked this button and voila - now I am my wife.
I didn't choose my Google account, it seems that it had synced with the one that was active at that moment (which was my wife's account, but not sure... may be not). Now, my old link to my profile says it doesn't exist. https://stackoverflow.com/users/7376567/gprost
But here is a new hybrid page (https://stackoverflow.com/users/6250385/elena-teresa?tab=profile) of my achievements and my wife's avatar. However, there are also some strange things: I don't have all the badges I had, and I think the reputation has some glitches too.
When I Log Out and Sign In with my email + password the result is the same. But here in Meta, I am still me, I also have link to my Stack Overflow profile in Meta Profile page (https://meta.stackexchange.com/users/349545/gprost?tab=profile) but it leads to my new hybrid page, and it also doesn't match with the badges I had.