Emotional exhaustion

I've been having a hard time lately with Sundays. They don't leave me feeling uplifted and strengthened like they usually do. I've been trying to figure out why that is, and I think I've hit on part of it.
I really don't want to sit by people who aren't my friends. And I don't mean by people who aren't friendly. Everyone in my ward is friendly and nice. I don't want to sit by those people who haven't proven themselves to by my friends. I only want to sit by people I like. I was explaining this to my sister today who is studying to be a Marriage Family therapist (hereafter to be MFT) and she gave me a list of reasons why I might feel this way. I finally said that I can't expend the energy to be nice to them, to reach out to them and that's when she told me I was probably emotionally exhausted. I am generally pretty physically tired too, but I do manage to get sleep (not as much as I should with a night job, but enough that I can stay afloat). But emotionally, I am just drained. I simply cannot spend the energy on anyone else, I just don't have it. Its not there.

I was doing alright until my baby sister moved in. I'll have to tell you the story behind her later, but the parts that affect this post are that she gets off work around midnight one o'clock, but doesn't generally come home until between 3 and 5am. And since I hadn't had time to get a key made, I had to wake up to let her in. This was not good. Then the other day she got up and I talked to her (normally one of us leaves before the other is awake) and she sounded just terrible. I told her she needed to take some time off, but she made some excuse. When I came home later that day, she was out on the couch because she had gone to the doctor. She has some sort of viral infection. She's basically been asleep at my house for the past four days. She just takes up so much of my energy, worrying about her because she's making stupid decisions, not sleeping or eating enough so she is basically killing herself and a variety of other things. Like her boyfriend coming over on Friday night and he made her dinner. I got up the next morning and found that he had used my food (technically its hers too, but its not his) and hadn't even done the dishes. I'm sorry, but cooking in someone else's kitchen and then not doing the dishes is really low. And I have to take care of some things for my mom too because she doesn't know how to use the internet. And considering I work all hours of the day and night, I just don't have the energy to care for anyone else, or to reach out to that poor soul at church that needs a friend. Its just not in my right now.

Maybe this summer when I only have one job.