I feel like I’m failing

I have two boys, 2 and 7 years old. I recently gained custody of my brothers two children who are 6 and 10. One was sexually abused and were working through that. The other one has quite a few issues we’re working through as well. I get no help from my boys dad, no help from the state as I make too much. I work a full time job plus I have a small farm at home and I’m doing online school. I am falling apart and have no one to help me and I can’t fail these kids as I had a shitty childhood and I can’t do that to them. I’m putting a stop to school for now and I feel like I’m failing but I have no choice. I work 70 hours a week so I barely see my kids but o have to pay bills. Not looking for anything but I just needed to get that out there. Ugh it can only get better……