Bormac

Ok so forgive, I'm a newb but I looked around a few minutes for this answer and can't figure out my issue. I can post a screenshot - but basically I loaded up a Custom game online with Fastest FPS, just one Easy AI (not Brutal AI selected), on a large map. Within seconds, the AI is at my base and destroys me. I literally don't have enough hands to counter this - it must be some sort of glitch? Am I doing something wrong in the set-up?