5 days on a coil with avg vaping ( 3-5 ml/day) ummm time to change the coil... its gunked up and making things harsh....
as the coil gunks up, the "carbony stuff" acts as an insulator ( heat wise) and the coil now needs to become hotter to vaporize the juice. By the time the coil is hot enuff to heat up the gunk buildup,it is trashing out what bit of juice that has soaked into the gunk... so in effect you are getting burnt juice ( harshness) but the burnt "flavor" is being masked by the fresh juice vaporizing on the outside of the gunk.... you may also might have noticed a reduction of overall flavor too...