not much action needs to be done
If I login and check I also see plenty of these

I've received 3 of those ransom emails recently, all the same
just ignore and delete
and yes, it contains an old password of mine that was leaked in a data breach

they're probably trying with that, but as long as you change to a new password it's fine

also, they didn't really send from your own email address, they just spoofed it, if you use an email client that lets you see headers, you can see the pathway it took and the real source

I saw this video where if your breach contains address and phone number, they even put that in and take an "image" of your house (via google street view)
https://www.youtube.com/watch?v=v_ZLbP9unZs