谢谢英子分享你的心得！再次欢迎你来美坛。

I agree with you and everyone above that improving communication skills is important. We all need to speak out when we feel mistreated. A suggestion of me would be: Maybe you could write down your thoughts, and invite M for coffee, and talk to her about the incidence, let her know it is not cool to treat you that way, and you don't like to be compared to the other Chinese co-worker that no one liked. Also you can tell her the consequences of her words, i.e. other people started talking to you the same way as she did, which made you feel miserable. She is making your working environment hostile to some degree (maybe not tell her this, that's just what I feel). 

Let's work together and make our job more enjoyable and less stressful!

good luck to you!