Transaction unconfirmed, send with Multibit HD, too low fee
As you have alread realised the Bitcoin mempool is currently (since the last 7 days) full of high-fee paying transactions. 

Unfortunately I do NOT expect the number of transactions paying such high fees to drop significantly during the following days/weeks. But eventually with some luck when not so many new high-fee paying transactions are broadcasted your transaction may be confirmed. 

MultiBit does not support replace-by-fee (RBF) as far as I know. Therefore you cannot do much more than sit and wait. If your transaction is not confirmed within around 1-2 weeks, then the network will drop if from the mempool and you can broadcast a new transaction with a higher fee.