Six weeks is early but you should be doing better than that, and the most likely culprit is heat management rather than seasoning. Two things almost everyone gets wrong with eggs on cast iron:
First, preheat properly and slowly. Five minutes on medium-low, not two minutes on medium. Cast iron is slow to heat and has hot and cold spots until it's fully saturated — a pan that's 200C in the middle and 120C at the edge will grab anything you put in it.
Second, the pan is probably too hot when the egg goes in, not too cold. Butter should foam gently, not brown instantly. If it browns the moment it lands, pull the pan off the heat for thirty seconds.
Also: don't touch the egg for the first 45 seconds. Egg protein bonds to metal and then releases as it sets. Poking it early breaks the release.