Is it the green bread knife, by any chance? That listing is showing as one sold on the 28th, with 2 remaining, which suggests that 3 were originally available. If you only have one left, you'll need to revise the listing to reduce the quantity. There should be a link to revise in the dropdown menu next to the listing in My eBay, or in the options listed at the top-left if you click to view the listing in full.
The item sold emails from eBay have been lagging quite a bit lately - I went for about 36 hours without getting a single notification from eBay, then they all came in within the space of a couple of hours (luckily, I was receiving payment notifications, but they can sometimes lag as well, resulting in no notice of a sale or payment, unfortunately).
If you can't see the order in my eBay, double-check that the sold list isn't set to show items for too short a period of time - it can be as little as 24 hours, so anything sold more than 24 hours ago will disappear from the list.
You can also check your selling reminders in eBay - the sections that has things like "I need to post X items" etc, if you click on the link in the "I need to post..." reminder, it should take you to a list of all items currently awaiting postage. Alternatively, if you view the listing for the item that sold, you can also see at the top that it shows some details for the buyer, with a link to view the order details, or "view purchase history" which will take you to a buyer list if there has been more than one, and there should be a link to print a postage label there.
