Transaction pending for hours:
When a transaction is pending for a very long time, it is more than likely that the processing speed you originally chose was too slow. We suggest that you cancel the transaction in your wallet and execute it again, but choose a faster processing speed. You can do this by clicking “Edit” on the swap confirmation pop-up from your wallet and clicking “Fast.” Please keep in mind that, yes, faster speeds mean higher gas fees!
If you are unable to cancel the transaction, then you may have a "stuck transaction." These are variants of slow transactions, but they take longer to revert. If you do have a stuck transaction, there's not reason to worry. Eventually, the transaction will revert on its own, and when it does, you will simply pay the transaction fee, without further loss of capital. Stuck transactions can be frustrating, however, because it's not possible to trade from a wallet when a transaction is stuck or pending. To avoid this problem altogether, we recommend using fast gas when possible, and trying to trade during low volume hours (Midnight - 5am UTC).