You are right, and I understand it, not from being an actual single parent, but because my hubby was in the Navy and away on deployment a lot. That made me a 'single' parent for seven months at a time. I remember one year when I was sick for over a month with a terrible sick headache, and couldn't get an appointment to see a Dr. My kiddos were in the early elementary years, and I would get up just long enough to wake them, couldn't even make their breakfast, because I was in the bathroom puking, and was only able to partially oversee them getting themselves ready and off to school from my bed or the couch. It was terrible, but we did manage to live through it. Thankfully those days are over, the kids are grown with children of their own, and I'm enjoying being the grandma and living near enough to help them out when sickness hits their homes, so they don't have to go through that kind of thing.
Hang in there, and know that there are others who understand. If you have some good friends, family, or neighbors who can give you a bit of help, do be sure to let them know what you need. People usually are happy to be of assistance.