Hi Jennifer,
I think there are two sides to this. The first is your sister's behavior and the second is to do with you.
In terms of your sister's behavior, my concern is the fact that it sounds like the situation has been going on for a while. This would suggest to me that her medication isn't at a therapeutic level and perhaps needs reviewing. If your sister isn't sleeping at night, does this mean she's sleeping during the day? If so the pattern of sleep needs reversing and maybe your doctor can help with this. If she isn't sleeping in the day, the disrupted sleep itself will have a poor effect on your sister's health.
You are obviously frustrated, angry and probably exhausted. Not knowing your circumstances makes it a bit difficult to know what to suggest. I would say that if your sister's moods can be stabilized it will clearly be of benefit to you. If you have other people you can call on to give you a break, or be with you, use them. Maybe ask about respite care to give you a break. In any case, I think I would suggest talking to your doctor about the situation and maybe seek an evaluation of your sister's care.
I do hope this situation works out for you.