A couple things come to mind:
1) Health issues. There’s a difference between just a really relaxed, low key day versus a day full of lethargy, which is a lack of will to do things caused be heavy stress, negative emotions (depression) or health reasons. If she’s eating, pooping, and peeing fine, this rules this out most likely.
2) Digestion. Rabbits like to nap after eating, so if it’s a larger input of hay after the sleep, chilling afterwards to get it through is not unheard of. Wick’s sleep and wake times literally revolve around food.
3) Owner activity. If you’re typically sitting in one place, not doing much (i.e. watching TV, doing work..), this will reflect onto your rabbit and make them less likely to run around in their own. Rabbits like to be in the presence of those they find security with a lot, so if you find yourself staying in one spot, try going around and cleaning or something. This may stimulate more activity. I actively try to get around with Wick so he stops being a lazy bum pretty consistently. This includes crawling up to him every so often just to be like “hey wassup” or offering my back to see if he wants to climb on for a ride. I also follow him when he goes to another room, just in case it Sparks a nice zoomie session from him.
The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.