Am I Missing something here?

Ghengiz Khan campaign, level 3: Into China. I get the villagers/siege stuff, without losing anybody. I get back to the mainland where there are resources, build a walled base in the cover of the cliffs, and promptly proceed to have a fortress that I built as fast as I could (10 minutes to castle age, walls, a castle, etc.) torn down by arbalests, scorpions, onagers, and rams. No matter what I try, they are the perfect counter. Skirmishers, scorpions, onagers, knights, longswordsmen, mangudai. Everything! I have no idea what all these idiots are smoking who think magudai are great. I just watched 20 of them get raped by five archers. They shoot, run away, shoot, run away, etc. and it makes them untouchable. 5 mangudai shooting at one arbalest just got killed without shooting him once. I am serious. What the fuck? I don't want to cheat, but I feel like the game is cheating. Even if I manage to fend off an attack, and start rebuilding, my peasants are all killed by the next wave, which literally comes less than a minute later. I feel like I have a bugged disc, and the AI is on insane difficulty, when I'm only on moderate! I play random map, regicide, deathmatch, all against the AI on the same, moderate difficulty, and I consistently win, so WTF!? I beat the Barbarossa and JoA campaigns without any trouble, what am I missing? I used to love the game when I was younger, but now I am quickly losing interest. I can't move past this spot without cheating, and I get angry every time I try to play, because the enemy is starting with bases with barracks/etc. and I have to run through hoops to even get villagers, and then I am swarmed by three teams at once. They hit imperial age within 15 minutes (I counted.), and swarm my feudal-age ass with arbalests! I feel like the dudes at the end of the Last Samurai! I don't have a chance! Please help me!