Transactions can't be "cancelled" unless a transaction that invalidates it goes on the chain. However, as the number of unconfirmed transactions grows they will eventually fill the assigned memory on the mining computers, so they'll look to evict some transactions starting with the least lucrative (ie yours). That's probably what happened to yours. You could just retransmit it though (or anybody could, if they still had it ) assuming it wasn't now invalid.
The above advice was correct (the problem was with the gas price) but incorrect about the nonce (the nonce has nothing to do with this, it's just a transaction counter to prevent replay attacks).
You could try 1.5 or 2 gwei if you want to be very cheap, but expect it to take a long time to confirm. The weekend would have been a good time to do it actually.