What she says: I’m fine.
What she means: Drusilla wanted to be good. She fought her whole human life to be a good, kind person even after being told her powers made her a spawn of Satan. Even as a demon, Drusilla plants daisies and attempts to nurture pet birds and mothers her dolls because deep down, she still wants to care for things, to be that kind, loving person she once was. But Drusilla can’t be good. Drusilla has no soul and no sanity. Her daisies wilt. Her birds starve. She manages to look after her dolls only by virtue of them obviously (though perhaps not obviously to her) not being alive and therefore having no needs. And she is so far gone now that she cannot even understand why all these things she tries to care for die. If the Drusilla who existed before Angelus twisted her mind could see who she was now, she would be horrified. And at this point, perhaps the greatest mercy anyone could do for her now would be to stake her.