Mom Problems

Hi everyone, my name is Cydney and I'm 15. For the past three years things have been really rocky between my mother and I. I have four brothers and I am a middle child and my mother constantly complains about how she is always doing things for her kids and has no time for a life of her own. It has become worse and worse as of late, and today she made a comment about how on the "importance scale in our family, you're really low," and also about how I would never be half the woman she was because I'm too weak. I don't know what to do anymore because she constantly complains about how selfish I am. Any tips on how to deal with this? My self esteem gets worse the more she does this and I can't seem to get her to understand what she is doing.