I hope you have really good backups of your Ubuntu partition (and Windows).
It is not recommended to run fsck on mounted volumes or partitions as this could cause further data loss or other unforeseen issues.
If you had a standard Ubuntu install with an ext4 filesystem it is better to use e2fsck to check the volume:
Code:
sudo e2fsck -f -p /dev/nvme0n1p5
If there are errors, stop and report them here.
Make sure the volume is unmounted before you start. If you can "see" your files I would first try and save them to an external drive or USB before running the command above.
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