Basically you have two options to 'get your money out of mycelium'.
You can either send your funds to another wallet/address of yours or you can import your 24-word-seed (which you hopefully backed up) into another BIP39-compatible wallet (e.g. electrum[1]).
To get your seed phrase out of mycelium you need to chose your HD-wallet -> Click on the 3 dots at the top right corner -> Backup -> write down your seed-phrase.
To get your seed into electrum you have to choose 'recover wallet' and then paste your 24 words in there.
[1]
https://electrum.org/#home