What should I do?

Well I am basically falling apart ever since I took this job and am taking care of 2 extra kids. I am honestly depressed about this whole situation. So let me just run down my day. I wake up at 6am to get to work by 7am. I work 8 hours, then its off to my SIL Jenn's house to pick up my niece and nephew. I get home around 5:30pm, get dinner going or picked up, find time to get the laundry done, dishes done, clean the bathrooms, and whatever else needs to be straightened up. We end up eating around 7pm, when thats done, I have to get my niece and nephew bathed, dressed and ready for bed, make sure my boys get showered and ready for bed, then its finally my turn to get showered and ready for bed and by then between the yelling at the boys and my niece and nephew, I don't get to bed until 11pm, and then its back up to do it all over again. I'm basically EXHAUSTED!! Don't get me wrong, my husband helps a little bit, but he could definitely improve on that a lot more! I guess I just needed to get all that off my chest, because I really don't know what to do! I have no life now. I think that maybe I shouldn't of taken the job, even though the money is really nice, I just had more time and wasn't so grouchy and tired before, and on the other hand, I think that if I just hold out, my brothers kids will be gone soon, and then it might not be so bad. I just wish someone could tell me what to do and make my life so much easier. I also wish I had a husband who would put a lot more effort in helping out more to make my load a lot lighter instead of bitching about me being so grouchy all the time and how I never want to have sex with him. Like thats what I really want to do after such a long exhausting day! I also hate the fact that my boys think that all I want to do is yell at them everyday because I just want some peace and quiet instead of being the ref. for their fights. I don't know anymore...I feel like when I'm working full time I'm missing out on a lot of things that they do at school, like award ceremonies, parties, and field trips. I hate the fact that when they ask if I can come, I have to tell them no because I have to work. Then when I'm at home all the time, I feel alone and useless. So thats why I guess I've fallen into this depression. Sometimes I just wish life was a little less complicated and things would just come more easily.