"only XL-3"

I was doing pretty well – 2 heroes with full control, 4 upgraded Necromancers, their stats were a bit worse, but not critically; 22 archers, 3k skeletons, wyverns, dread knights + 3 built Necropolis cities. But how do I stop myself from rushing on the 5th week outside the city? I exposed my entire army to a trap.
Thanks for the game!