I have no idea why it become a low priority transaction.
It has a size of 2KB, the fee that you included was too low for miners to include it in a block. Also, it gets worse because of the ongoing BC attack
Will I lose my coins?
No, once the TX drops from mempool you'll get your BTC back
Which client did you use to send the tx? Shorena might help you with double-spending the transaction with a higher fee