A couple of days ago, I had a transaction take 1 hour to confirm! Never had that before, and have since increased the fee I pay in the hope of avoiding that in the future. I wonder if the network is becoming overloaded.
it really depends on the transaction fees you paid and how many unconfirmed transaction are in the memory pool currently (you can check it here:
https://blockchain.info/unconfirmed-transactions)
so basically the miners will pick up and include in a block the transactions that pays more fees than others so if you pay less fee, you will need to wait probably a little longer to get a confirmation