First trying to feed that offten might be stressing her out..

Here try this.. Loosely crumple up some news paper and put in in her tank all over, making sure none gets in the water bowl.

Leave her be for a week. No cheating! Check her water if you like but don't mess.

After a week get a live mouse and offer in late at night. Just put the mouse in and leave it.

Try that and see how it goes.