I am in a similar position although a bit better. I wasted time getting Padme rather than work on Darth Revan and may not end up getting him this go round. I have had some great, close matchups (some wins and some losses) and a few where I have been blown out completely.
It stinks to get blown out but there isn't much that I can do in the short term. The best thing is to remember that this is a game and is supposed to be fun. In general, if part of the game isn't fun, skip it. That said, the rewards from GAC are good to get. Fight the battles that give you a chance, get as many points as you can for defense and take the rewards you get. Don't sweat your rankings and don't waste time trying desperately to win when you have no chance.
Keep building your roster and concentrate on the meta characters.