Emma, I feel similar to you on that type of statement. However, I think someone saying they relate to me is a lot better than someone saying "I know how you feel", or "I feel the same way". The fact is, no one knows exactly how you feel. Therefore they cannot feel the same way. They may have an idea of how you feel, and thus can feel similar to you, but not the same.
With that said, I also know that the above statements are used by others to try and comfort and validate you. It is tough at times, but I try and keep that in mind when I hear statements like that.