Other people are using my email address

Delete, block and don't open anything you are not expecting !!

We all get spam e-mails. They do it in the hope you will respond and then they've got you hooked.
Some are down right dangerous and wreck your system.

But these are not spammy-looking! They’re receipts for purchases, minutes of meetings, invitations to meetings and such like.
I’ve built up quite a detailed picture of the Daddima impostors!

Here is a question the Google help forum from someone else with exactly the same problem.

productforums.google.com/forum/#!topic/gmail/8j8P2tdgeKQ;context-place=forum/gmail

I would change my email address and send your new one to everyone trusted on your list.
Then delete the other email address.

I had to do this a while ago - but you will have to re-register with GN and choose a slightly different user name (or totally different if you fancy a change!). I had to add some numbers.

In your position I would cancel that email address and get a new one which was unique and not likely to be used by someone else.

I've had a similar problem, too. I've apparently spent an inordinate amount of time in Uber taxis, driving round Zanzibar!