Does it come out, walk around, eat and head back purposefully or does it seem lethargic?
If it does then it may be babies. If it seems lethargic then it’s likely sick and you need to get help/advice
If you listen at the box you may hear the babies rustling around when mum is in there – or you may hear them call for her – it’s a high pitched peep ( a bit like a smoke alarm when the battery is going )
If it is babies then she has opted to have them there so I wouldn’t worry about it. Keep a look out as the more adventurous babies may stick there heads out at about 3wks
