If you forget to stir your gravy or have the heat too high it can easily burn. Thanks to this tip from Tipsopedia all is not lost, thankfully: pour the burnt gravy into a clean pan and add sugar to it a little at a time to take away the burnt flavour.
Photo by Ray Dehler.
I'd start with half a teaspoon and work up in that increment until you find the right balance. Add a half teaspoon of sugar, stir, then taste and repeat until you've got your groove gravy back.
Burn Gravy Remedy [Tipsopedia]