E.J.
It's normal for kids' sleep patterns to change. She might have been scared by something that is giving her nighttime anxiety now. By reassuring her you will help her to feel safe and comfortable in her room again. Stand next to her bed, hold her hand, rub her feet/back etc. I also would play white noise or lullaby music if you currently don't. Does she have a nightlight? Maybe one of those pillow pet lights. Maybe get one of those microwavable toys with lavender scent in them. Try to make bedtime as soothing and relaxing as possible. After a few nights when her anxiety seems to lessen I would tell her that you will be right back, and leave the room for a few minutes. Make sure to come back though, this will reinforce to her that you are near. Each night make the time that you leave longer and after a while you will be able to leave her room after laying her down.