Game Crashes

Several times today, my game seems to crash and disconnect me from multiplayer. This appears to happen when there are too many units on the screen at once. For instance, I was just in a huge battle with my opponent, when I decided to spawn a Retriever Sentry (playing as Anders) and all of a sudden the frame rate drops, the game freezes, and after about 4 minutes I am kicked from the game. Has anyone else had a similar problem?