Looking for drama where the female lead is totally messy. Either doesn't care about her appearance, behaviour, or generally just has a messed up life.

Thanks :D

Uncontrollably Fond -- I think everything in your criteria fits the main female lead in this drama.
Koi no Chikara: aimless life (at least in the beginning), a bit of a mess in the house
Last Cinderella: her house is a pigsty, to be honest
I can hear your voice  her house is also a pigsty :D
Tomorrow Cantabile
Flower Boy Next Door
Nodame Cantabile
Hotaru no Hikari
Ohh watch Attention Please. It's J-drama. Female lead is messy and the drama is funny too!
Surplus Princess (K-drama), Coffee Prince (K-drama)
Another Miss Oh - Girl was dumped the day before her wedding and her life is a bit messy because she can't handle it. Even her parents kick her out of their house, they can't comprehend her anymore and also want her to wake up.