I realized I had the base unit set to mBTC. Changed it to BTC.
Now I have a balance of 0.00005388 BTC. The lowest fee it will allow is 0.00005 BTC. So I am in the same situation.
Am I right to guess that the balance I am trying to send is too small for the blockchain, and I need to add more BTC to my wallet to make the 0.000005 fee worthwhile?
The smallest you can send is 1 satoshi which is 0.00000001BTC but it would be considered a dust and nodes would not relay it. The lowest output you can have in a transaction is 2730satoshis before the transaction is considered as a dust. You should add more BTC but not with lots of transactions. The more inputs you have, the higher your fee would be. If you don't want your transaction to get stuck, you can also use dynamic fee.