750cc saline under the muscle. I just had my surgery last Wednesday and I look very buff and flat chested?

Since the implants are under the muscle you my be seeing a flattened effect.  Your look will change as healing progresses, the muscle relaxes, and the implants drop into the pocket.  I recommend discussing your concerns with your surgeon.  it can take 3-6 months for final results from a breast augmentation.

At one week you are only about 4 percent shaped. Your muscle has the implants pressed flat. "Drop and fluff" refers to the fact that as the skin stretches and the muscles relax, the implants move down and out slowly – about 1 percent a day. It’ll be about six weeks before they even begin to settle down, but they’ll be close to 80 percent settled at three months. Watching their progress is like watching your hair grow. You don’t see a difference in your hair growth daily, but all of a sudden you need a haircut. 
Be patient after surgery. Give yourself a few months before making a judgment about your surgical results. You won't know the outcome until then.
Dr. Ted Eisenberg, Board Certified Plastic Surgeon and Author