Air factory was a bad idea. The bombers didn't really accomplish anything and just detracted from your ground forces.
I think the main reason you lost was because of your ACU placement. You need to use him to hold mex. Lainelas moved his ACU up to the top-left area, allowing him to gain those mex, while your ACU just hanged around the middle, not really protecting anything, or raiding anything. Lainelas just had more mass than you.
Also, I think you could expand for mex faster at the start, and reclaim more later on. That's another thing your ACU should fight for.
I really don't know what to do against him
Some pointers would be nice.