Matchup Imbalance on Team Builder

Ever since the new summoner's rift, I've lost almost every single game. Some times I'm having an off day, or make a stupid decision here or there, sure, but the problem stems from the fact I run into high elo smurfs and plat or diamond players on the other team, and mine doesn't have any. The opportunity to play them is nice, but its getting tiresome loosing all the time.