Who am I?

Why is it we eventually believe what others say about us? Maybe I'm the only one who feels this way, but I grew up with one particular woman telling me things about myself that I started to believe she was right. Why is that? When I had first met this woman I looked up to her, thought she was cool, therefore she had my respect and attention. It seemed like the minute she realized that she started beating me down. She would tell me I was selfish and hypocritical. That I had a major depression issue, I was fake and unreal. This didn't leave me with the best confidence, however the more I matured in my faith the more I realized that I'm not those things. It didn't end though. Another woman I desperately wanted a relationship with started to feel the same way about me. In her opinion I was a terrible person. I was told by her that I think I'm "higher" than her because I'm a baptist and she barely attended church. I changed someone she loves dearly for the worst because that special someone to her started attending a different church, became a renewed Christian and Christ started showing through his/her life. So once again, I started to believe these things. Only this time the feeling didn't go away and yet another woman I loved dearly said the same things about me.
This is one of my greatest struggles today. I'm the type of person who takes things to heart. It could be because I grew up with the one woman telling me these things daily or maybe not. why is it though? I thought I would become bitter about these women. I think with one I kind of am. But with the other two...I feel like an ant to. with the second woman I mentioned...I can't be myself around her. I'm always doing something to offend her or something she doesn't like. What do you do in a situation like that? Especially when the relationship has to be there for someone elses sake. I have no idea. I do know that God has given me so much strength through all of these situations. My faith really rocketed while I was growing up being called those things. However, it's only grown through every other situation as well. He is faithful and I know these relationships will be mended somehow. Through Him I find that I am not those things!