received notice someone using my apple id
I just received notice that someone using my Apple ID signed into Facetime. It was just a quick pop-up screen which I clicked "Okay" on. I can't verify! Is this another Apple glitch? Lately I've been having to unlock my account a lot. I can't use two-step authenticity because I don't own a cell phone. How can I verify that someone else is using my ID?
iMac Pro