<human>: Give me the gist of the text in a nutshell

I dated a really nice girl for about 6 weeks and we spent almost every day together during that time. We realized things were going too fast and we ended things because she had just gotten out of a relationship and I am possible moving for my career.  After we broke up we still talked every day and would laugh and talk like normal but all of a sudden she is now being really mean and standoffish. I have no idea why she is being like this and it stinks because I feel like I am losing a good friend. 

 I am pretty aware that it could be that she does not want to talk anymore but I am not sure why all of a sudden she is acting this way. She said in the past that she wants to protect herself from getting hurt by me so I am not sure if that has something to do with it.  I don't think it is another guy in her life as well. I really just have no idea why all of a sudden she is being really mean to me. 

Also, I know 6 weeks is not a long time to date at all but we got along really great and I have never felt that good about a relationship that early on before.
<bot>: I really want to know why all of a sudden my ex who I was really close with is being standoffish any advice will help.