What should you do if the exercise schedule you make yourself is not working out well by midweek?

Stick to the schedule anyway. Learning what does not work can be just as valuable as learning what does work. You can reevaluate the schedule at the end of the week and change it as necessary.

You shouldn't expect instant results from anything like an exercise schedule, a diet, etc. Anything that involves a change in yourSELF, like forming a new habit or breaking an old one, is very tough to pull off, and it's going to take some time. Before you decide how it's working out, you should make up your mind that you're going to slog through it for at least a MONTH, doing the best you can but not expecting perfection.

This is my personal opinion. I could be wrong.