Mead is particularly difficult to ferment because of the high sugar content from the start. Yeast needs certain things to work and some things can cause it to stop working. So in breadmaking salt and fat will cause the yeast to slow down, dough which is enriched with fat and egg - bun types need more yeast from the start to counteract this. In a fermented drink, excess sugar or lack of nutrients will cause the yeast to slow to a stop sometimes. A country type wine made from say elderberries usually has about 3lbs of sugar per gallon, and it is better added in 2 stages. Mead already starts out with more than 3lbs of sugar and honey has a distinct lack of nutrients suitable for yeast which is why yeast nutrient is added, tannin is also a necessary added ingredient in mead. Grapes which are the perfect wine making fruit have their own built in tannin in the skins and pips, cider apples and perry pears also contain tannins. Tannin adds "body" to the drink and wines/ciders with no tannin can taste weak and insipid.
Nopants your mead will have fermented a certain amount, but despite the fact that it has cleared it has not fermented to a finish. Mead will clear easily because there is nothing in it like fruit pectins to make it cloudy, the clearness of the mead does not denote it has finished fermenting. The way to test for that would be to check its alcohol content. Modern yeasts will take a wine to a maximum of 17% before the alcohol content kills the -yeast. Home made wines will start to re-ferment for all sorts of reasons. Often in a country type wine the re-ferment started again to coincide with the fruit blossoming, this of course also coincides with warmer weather. Mead will stick at a certain point only to restart later. It will take at least 3 months to finish. Put it somewhere warm and forget about it for the time being.
Frisbee