My older sis had an ectopic pregnancy, and my younger sis was told she would have one too.. being the middle daughter, am i at risk as well?

Not necessarily: If it was a physician who has taken a history and examined your younger sister telling her of increased risk you would certainly want to ask why. If someone just threw that out because your older sister had an ectopic then i would not give it a lot of weight. Family history is a factor but prior problems in the specific individual such as infections and surgeries usually play a bigger roll.