Avoid sending harsh or demanding emails or messages when you are panicked, frustrated, or angry. Walk away from your computer and return at a later time when you feel calmer. Then re-read the instructions, or syllabus, or the course materials you find confusing, and if you still cannot find the answer because it is not there, definitely email or message your instructor.
Even if you are under pressure, it is best to stay respectful and know that teachers or professors are humans too. You can not only always resort to your teachers, but also can look at other sources. This may include instructions to conclude whether you really need help or if your questions can be answered easily with what was given.