Some people think they are the same thing. But...they are definitely not.
I love Glӧgg probably because I love sweet drinks and fruity wines but I am definitely not a beer drinker. And Mead is more of a beer-type drink while Glӧgg is a sweet wine drink.
Mead is an alcoholic drink made by fermenting honey with water and it can have other ingredients like fruits, spices, grains and hops, where the hops create a bitter beer flavor.
The main ingredient in mead is honey that has been fermented and can be carbonated, sparkling, dry, semi-sweet, or sweet.
While Glӧgg is always sweet and is made with wine.
These are very different types of beverages and just because you like one doesn't mean you'll like the other.