-Sleep ABSOLUTELY contributes to weight loss. If you aren't sleeping enough, you probably aren't losing weight. 8 hours is ideal. Sounds like quitting that job may benefit you.
-Like a few people have said, you may need to increase calories. Additional tidbit... try and make those calories protein. During my last plateau, I didn't have calories to add so I changed my breakfast to a 30g protein shake and 2 days later I was down 2 lbs. Some research says the body can't actually absorb more than 25g protein at a time, but whatever it was on sale and it worked.
-I had a friend move in with me when she was down and out. We worked together at a restaurant. Luckily my manager gave me the advice to have the "when are you planning on moving out" convo a day after she actually moved in. I'll never be able to thank her enough for that advice! I'm sorry you don't have that option, but here is what helped me. Hopefully you can adjust something to make it work for you. The biggest thing for us was that my lease was up in 2 months. I actually told her that she could crash on whatever couch I had, but it did seem to give her more motivation anyway. Maybe you could put a time limit on it. Some states require 30 day notice even in this situation. So give her some written notice. I was looking for a place so whenever I came upon a place that fit her- i sent her an email with the info. I know its extra work for you, but you could do that if you want to motivate her. My friend couldn't save money, it was like she was allergic to it. So I made her give me all but $20 of her money at the end of every shift = No tattoos for her! She had enough to move out by the time my lease was up. She also stopped buying junk food since she would save the $20 for more important things- like alcohol- whatever, at least the smell of Jack Daniels didn't make me hungry
. If she isn't willing to do that, you could just start charging rent and save it so you can kick her out guilt free in a month. She'd probably be more motivated to move out faster if she wasn't freeloading.
-The best part about these little things is that they are taking strides towards your goal and hers. Just knowing that progress is happening removed so much stress for me and my friend. She was not happy about me taking her money the first day, but by the third day she was excited to give it to me. Of course waitresses have a huge amount of instant gratification and she saw the numbers add up fast. Not sure if any of this will help you, just offering a little different perspective than the "just kick her out advice."