1. You can do this. It will feel uncomfortable at first but you will get into a groove and you will get through this.
2. Kids do NOT need to work for 6 hours a day to learn something. They don't get a full 6 hours of learning in a school day, and you shouldn't feel pressured to spend 6 hours keeping your kids stimulated. In fact, you may find that your own kids need more or less time to learn something.
3. The best way to reinforce learning is to talk, talk, talk. Rather than opting for more worksheets or quizzes or reading, try putting the materials aside and just talking about the content. Some of the most memorable conversations I have had with my kids have been about obscure topics like microbiology or Ancient Rome or the Oxford comma. These chats will help cement the content in your kids' minds. It's the kind of activity that your kids' teachers wish they could do, but never have the time to do.
4. Take advantage of non-work hours. Kids don't always have to be learning while you are working (unless your district requires it). If it's easier for you to homeschool after work, during the day you can give your kids the freedom to read for leisure, play games, or just look at a screen (gasp). It's OK. You need to do what you need to do to achieve balance. It doesn't make you a bad parent if you allow a little more screen time during this emergency.
5. Let your kids sleep in! Take advantage of the fact that your kids can reset their biological clocks and get the rest that they need but cannot get during a normal school year.
6. Take care of yourself. You are taking on much more responsibility now. Don't forget to indulge a little (or a lot) in self-care. You know the whole mask on an airplane analogy. You're no use to anyone if you are burned out.
7. Stop trying to be perfect. There are well-meaning people tweeting schedules and activities. But, this adds to the pressure to be a perfect homeschool parent. Let it go. Don't compare yourself to others. Do what's right for your own kids.
Above all, be safe!