The Ethereum network can have large fluctuations in usage, causing swings in fee prices and resulting in some transactions to remain unconfirmed for long periods of time.
When this happens, please be patient and wait for the transaction to confirm. Sending new transactions will NOT make the current one confirm any faster. The way Ethereum was designed by its creators, new transactions are added to the end of the queue, so they will also remain unconfirmed waiting for the previous ones.
Future app updates will include several features to mitigate and resolve such issues, including user-selected fee priority, manual nonce override and one-click solutions for speeding up or cancelling pending transactions.