It sounds like she is exhausted, 2 jobs and school is enough to cause exhaustion in anyone but with everything she has been though on top of that it sounds like she is getting worn down. Keep in mind working a lot of hours and going to school such as this is a lot to handle for anyone. Add the fact that she has recently lost family in recent months and the fact that she lives with someone who is drinking all the time it sounds like things are getting to be to much for her.
I also suspect she may be suffering from depression which is very serious. Sleeping more then normal, unhappy with her self etc is all symptoms of depression which is likely stemming from all the hours of work and school along with all the other problems she has undergone recently.
I know this can be quite frustrating when you are in a relationship, but right now she needs you to be strong and help her. I would suggest that you speak with her and let her know how worried you are about her. She really needs to set up a appointment with her doctor to go over her symptoms and begin seeking help. There are medications that can help her, and she may need to take some time off from work or consider working less hours until her schooling is over.
Right now she may want nothing more then to start a life with you, but it sounds like you are starting to resent where she is right now and the last thing she needs is to know how much this is upsetting you. Right now she needs support and help to go see her doctor and get herself back on track.