My cat has randomly started peeing in our bathroom...help!?

This is a new thing. She normally goes outside to use the bathroom. She first peed on the bathroom rug the past 3 nights...now this morning she peed on a pair of flip flops left in the bathroom. Is there anything we can do to stop her? I can't get rid of her...she's so sweet!!!!! :( And no she won't use a litter box.