If the holidays are annoying you, one option would be to adjust your season length in Settings. The default 7-day seasons mean you'll get a holiday once a week, but you can lengthen each season up to 28 days.
Otherwise, yes, you can spend the day increasing work related skills, or reading journals from work. If your sim's a workaholic she can work from home on the computer. And she may be able to get a promotion or raise by chatting to her boss and asking for them. The medical career track often requires your sim to come into work at odd hours for emergencies - it's possible these will still happen on holidays. Good luck!
