Sorry for the headache. Cart history is associated with a token stored in your browser's cookies, so if your cookies were cleared (or you switched to a different device or browser), the information would have been lost. You may want to try using the device or browser from which you were building your cart previously to see if your cart contents are still available there.
If you have a fan account, we recommend adding items to your wishlist instead. They’ll be saved forever, and available anywhere you log in. If you don’t have a fan account, you can sign up here.