Why does my bunny stop eating so frequently?

[bridgyj1]

My bunny "Tinker" is nearly three years old. She is a standard rex. Every so often she stops eating and gets really lethargic. I can tell straight away if there is something wrong as she is just not her normal bouncy self. Rabbits need to constantly eat and can die within a very short period of time if they stop eating for too long. With many trips to the vets and varied explanations, changes of diet etc. all I am able to do is give her Metacam and hope she gets better each time. Can anyone shed any light on this? It is all very worrying and also costly.

[boxtops]

I don't know what Metacam is - is she in season by any chance?