I'm sorry you experience this issue. It is caused by the update to version 3.7. The database structure has changed and your existing data needed to be migrated to the new structure. This migration leads to a faulty sort order of playlists for some users. Unfortunately you seem to be affected.
If you have a backup file, you can restore this to get your old sort order. If you do not have a backup file, you will have to reorder manually. At least this problem will not happen again as the migration is a one time operation only done when updating from 3.6 to 3.7.