There is just no communication at all between us. She sleeps constantly all day (not at night). She acts angry and unfocused and stays in her very messy room all the time. The only time she comes out is to eat. She has aches and fatigue, weight gain, hair loss and skin problems. She does not look after her health. I don't know how to communicate with her. She is not open to any suggestions. How do I get through to her?
I don't know how to communicate with my adult daughter
That sounds awful, and is clearly unsustainable. There are some great answers that give some guidance about what might be an underlying condition. If all physical and mental health issues are ruled out, it's time to take action. Get backup from friends or family members if you need to, but let your daughter know you are giving her 30 days notice. She needs to find another place to live within that time. If she wants to stay with you, be clear that first she has to go, with a potential to return after she has been out for a good chunk of time. Once out, she can prove to you, and more importantly to herself, that she is capable of maintaining her health and her environment. Remember, you are going to rule out issues that would make it impossible for her to be successful; if she is in good health, her staying with you and living this way is actually harming her.