Bitcoin spends outputs from other transactions. A transaction can only become confirmed if all of the transactions that it spends outputs from are also confirmed. If those previous transactions are not confirmed, then the transaction will not confirm.

The source of the problem is https://blockchain.info/tx/a80d093e497b854a94e176c339d1b8bf3996f213f9f921cb91aaa7f6597da893. This transaction was holding up the chain as it was unconfirmed. It had a relatively low fee and a large size. Fees are based on transaction size (as in the size in bytes of the transaction).

Since that transaction has now been confirmed, all later transactions (including yours) are also now confirmed.