It sounds as if there has been either a change in her environment (as Logan has suggested) or their is something physically wrong with Annabelle. On the environment side...some more suggestions: Has anyone she knows gone on holidays, Is there a new cat in the 'hood (if she's an outdoors cat). On the health side - cats will sometimes try and let you know if something is wrong by attention seeking acts like Annabelles. Is she actually going to the toilet normally or is she straining or producing small drops of urine? It sounds as if you should get Annabelle to a vet for a check-up - There could be a 1000 reasons why she is doing what she is...I'm not suggesting anything is wrong but it is better safe than sorry.

Good luck - let us know how things progress...Troy.