I just can't deal with Eldar as Space Marines.

Obviously, the key to the RTS is basically to gather as many resources as possible and use them as fast as you can to build up a force and research tech. But I can't get any resources...

1v1. Game loads and Eldar base units just wipe out my forces. In my last game, the guy just walked straight up to my shield generators with 1 starting unit. It took me a total of 2 Assault Marine and 1 of the basic just to kill them all...

erm, WTF am I supposed to do about that and in that back of my mind I'm aware of how many resources I'm spending just to stay alive and I know he's taken 60% of the map by now. Exactly how am I supposed to compete?

Am I supposed to just sacrifice the map and try and turtle? That doesn't seem viable considering just how much damage I am taking