Maybe it's because you care and respect them so much and had chosen to place them above yourself that their thoughts and opinions now matters so much to you than your own opinion. You can either chose to let them continue to bring you down or stop them NOW. The choice is yours.
I think people who are trying to bring people DOWN are already DOWN and are just tryin pull down people whom they feel are above them to come down to their own level of esteem. When they successful bring you down, they use you as a reason for them being better since they've successfully made you worse. When you feel worse, they then have a reason to convince themselves that they are better and so should (or deserve to) be happy now that you're worse than they are... You feeling down encourages them to believe you are guilty of their accusations. NO ONE CAN BRING YOU DOWN WITHOUT YOUR AGREEMENT. That's how powerful you are. You have to agree for their opinions to matter, else, they can eat them back. 
