In trying to set up a Gmail account for a friend I clobbered my own Google accounts

My friend has a computer which I find hard to use.  My own computer I am 
completely familiar with, of course.

I thought "Setting up a Gmail account for her is completely in the 
cloud, so it shouldn't matter which computer I use."

Unfortunately, doing it on my computer somehow caused Google to see 
"her" account as just a re-naming of mine.

So I am now <her.name>@gmail.com.

I *am* able to change all my personal information back to my own.

But when I try to change the email back to my own email, I get

	[This is] "the address used to identify your Google Account to you and 
others. You can’t change this address.

("This address" meaning <her.name>@gmail.com, of course.)

*All* of my Google data is still there -- just under a different email.

(I am immediately going to download the data, for safety.)

How do I get my Google account back with my own email address as my 
identity?

-- 
Dudley Brooks, Artistic Director
Run For Your Life! ... it's a dance company!
San Francisco