Confirmation time depends on a transactions miner fee and the miner fee should be sufficient or higher for your transaction to not get stucked. You can use this site https://bitcoinfees.21.co/ and as well as view if the mempool is loaded or not to get the most accurate fee before sending a transaction.

Now, since its been seven days already, Your transaction must have been forgotten/expired by the network as it has remained unconfirmed for too long and thus the coins should be back to you. Can you post your TXID here if you still have it? otherwise check if the coins are back