Natural Health: What can I take to ease a sore throat?

It is interesting that you have identified stress and fatigue as factors in developing a sore throat, as both these situations are known to impact immune function, leaving us more vulnerable to illness.
Gargling with salt water is a great place to start. It works by reducing inflammation and swelling, loosening mucus, and creating a hypertonic environment that makes it harder for some bacteria to thrive.