Hi @jskahan ...
When you deleted your e-mail notification, do you know if that message went into your deleted folder within your e-mail client? For example, if I look at my personal e-mail account on my iPhone, I can access my Inbox, my Sent mail, and even my Trash folder...which is where e-mail messages go to if I delete them from my Inbox.
Or, are you referring to a message that you were viewing from inside of your Canvas Inbox (by clicking on the "Inbox" button on the left side of your Canvas environment)?
If you aren't able to get to your message using one of the suggestions above, you may need to reach out to your instructor to ask what those dates were. You can contact your instructor by following the steps in this Guide: How do I get help with Canvas as a student?
I hope this information will be of help to you, Jared. Let us know if you have any questions...thanks!