[Sans-Culotte]

But the most worrisome zinger is sometimes the yahoo sign in window says my "password has been changed in the past 3 months" which I haven't. And sometimes it says it is sending a verification code to some email I've never heard of. I'm guessing it's been hacked???

That is what it sounds like. The hacker got into your email and changed the password and gave a different email address as the one to be used for verification.

[butlerweave]

yahoo sign in window says my “password has been changed in the past 3 months” which I haven’t.

Windows 10 popup says that all the time ,LOL