If you can't explain it to your boss, just stop shielding him from the consequences.
When you can't do all the work without getting exhausted, prioritize it, do what you can, let the low value work pile up and people complain. If you can't switch all that fast, don't, or if switching is more valuable than your main work, do prioritize it adequately, what means pushing the attention requiring work down.
And do care about your healthy. Make sure you exercise, get some sun, and control your caffeine intake.
When you can't do all the work without getting exhausted, prioritize it, do what you can, let the low value work pile up and people complain. If you can't switch all that fast, don't, or if switching is more valuable than your main work, do prioritize it adequately, what means pushing the attention requiring work down.
And do care about your healthy. Make sure you exercise, get some sun, and control your caffeine intake.