I feel for you. With a baby, what you are managing is just what I would have done. I don't think I have done anything different. I work from 4:30 a.m. till 1 p.m. now and I have 13 months old baby, 7 years old, and 9 years old. My husband watches my kids and when I get home, he just left it all to me. I have to stay awake until the kids go to bed at 9 p.m. and the baby doesn't sleep until I sleep, which would be around 10 p.m. to 11 p.m. That's about 5 hours sleep that I have every day.
But before that, I had a job that I go from 6 p.m. till 3 a.m. and when I get home, I had to wake up at 7 a.m. and walk my kids to school, then walked back home and sleep some more until 11:30 a.m. and walk to get my girl (she was 5, now 7) then walk home and waited until 2 p.m. for my boy, then back home, cook up dinner, nap one hour then drive to work at 5:30 p.m. I was living in Los Angeles, California at that time. It was harder because if you are late more than 10 times, they will file a report against you with District Attorney for children being truant.
Now, to answer your question, you are now a grown up and there's nothing you can do about your schedule. I wish there is a better way. The only suggestion is find another job that you can work during day time and get day care. You will get refund in day care expenses through tax refund, so no loss for you. Or one of you get a job that pays as much as two of your incomes combined so you can quit and stay home. Nice dream, huh?
I do wish to sleep more. But I know it's not going to happen until my kids are all in school. It's going to hurt at first, then you will get used to it until your baby's in school.
Sorry for the long response. Hope this help. The best I can do is encourage you to be strong and try to stay healthy. I drank Rock Star to stay awake at work. Exercises also give you more hours to energy. Try them?
:)