Relationship help please

So I have been dating this girl now for almost 4 months. I haven't been as happy as I thought. She is a great person I just don't feel the same connection for her that I did at first in romantic way. I feel that if I break things off she will be heartbroken. I don't really want to hurt her but I also don't feel happy in the relationship. She has moved quite fast and is already saying I Love You and she is very much in the relationship for the long run. I don't know what to do. Do I stay with her to not devastate her or should I do just that and end it? Any kind of help would be very much appreciated.

Dear MAM91...you obviously feel something for her, but ultimately it is very early in the relationship, and so she should recover fairly quickly. Have you considered that maybe you don't want to buy her a christmas present? If she is a great person she deserves to be truly loved by someone else, and that person is not you.