Ranger - "Higher Vampire" [5th Campaign, 5th Mission]

I can't handle it... It's true, this is my first time trying, but my 150 hunters and 80 druids + some other minor units, which are killed with a single hit, can't withstand 6+ skeletons with freezing arrows... Do I really have to replay the entire campaign now? The hero isn't the strongest, and he also went into "magic," but what kind of ranger is a magician? Knowledge 17, spell power 16, attack and defense at 13... Well, who asked him to put most of the "points" into knowledge when leveling up? The magic is useless... He only resurrects 36 elves at a time, and they get wiped out by a single shot :(