Are emails that were sent to me while my iCloud storage was full just gone forever?

So my iCloud storage got full today & I’m just a little concerned because although I’ve fixed the problem since then by deleting old emails & freeing up space as well as upgrading my storage back to what it was before it knocked me off this plan & back down to 5 gb when it got too full.

there’s absolutely NO way at all to see the emails that were sent to me today but that I couldn’t receive?? There’s nothing I can do with backup/restore or anything?! :/ or even another cloud storage app? Also- what are some good solutions to prevent this from happening when/if my storage gets too full again & stops allowing me to receive emails? What can I do to make sure this doesn’t happen again?