You could try spraying her bedding with PRESCRIBED flea treatment
(not an over
one, as some have been found to be toxic, even though they are cheaper) -AND then boil-washing it afterwards. Make sure there are no traces of detergent or fabric conditioner in it when it is rinsed. So make sure it's rinsed very well.
What sort of food does she eat? Is it good quality, with meat/fish as the first ingredient -and NO corn, additives, chemicals, by-products, fillers, or colouring?