Monsters please stop attacking already this is insane!
Welcome to the realities of a large frontier realm. Until now, you've mostly been shielded form the monsters by Caerwyn to your east and the Zuma to your south. But now Caerwyn's gone, all those rogue-spawning regions have taken their place, and you're trying to hold more territory than you've ever had to deal with before.
If you want to be a big realm, then you have to act like a big realm. Because, honestly, with a 6K CS army you're going to be quickly reduced to the tiny little thing you were before all those Caerwynians joined you. You simply cannot defend the territory you have with that tiny police force.
Why do you think Astrum has a nearly 35k CS army?