God no, don't make up a girl! That would be bad. If she really knows you like you say, she would know it isn't true. From what you have said about your chat, it seems to me like she does care for you alot. I think she knows how much you like her, and doesn't want to hurt you by going out with other men, but at the same time doesn't want to lie to you about doing it. I think she got upset because your her best friend and she can see how much she is hurting you without even meaning to. I definatly would advise not to look into it too much, cause the conversation to me looks just as if she is upset to hurt you. At the same time, it sounds like she really doesn't know what she wants at the moment. She has just moved to Uni which is a big step for anyone, so she is meeting new people and will have loads of new experiences in her life. So at the moment, just be there for her. Try not to act differently to her, cause it sounds like she needs you right now just as much as you need her.