I need help with annoying friend?

So my friend has really been annoying me lately she seems to copy everything i do. From stuff I wear to the major I chose. It doesnt usually bother me but she just is really annoying. She also has to know everything that is going on in my life and everyone elses. She constantly gossips. If i write something on twitter or facebook she has to know exactly what i am talking about..and if i dont answer she will bring it up days later and wont forget. I feel bad getting annoyed with her but sometimes i just cant take it. She also kinda lies sometimes. she will tell me one story and then when we are with some other friends she will make it seems better then what happened. I guess I am asking what I can do to let her know that she is annoying me because she doesnt take hints very well. thanks