Hi and welcome,
Unless there's been a recent change that I'm not aware of, I'm pretty sure you're correct about the email reminder for renewal. Maybe it got hung up in an anti-spam filter somewhere that didn't recognize the address?
If you right-click on the toolbar icon and select About, the "Registration Key" item will let you know when your current registration (which you need only for updates) expires.
But keep in mind that's all the email is, just a reminder -- you don't need it to re-register. You can re-register at any time
here, which will start a new period for you once you've plugged in the new reg. code you'll get sent.
Best,
Mike