I Can Be Socially Awkward Sometimes

We used to talk a lot and laugh together but dunno why I talk less to her lately and she feels like I ignore her so it doesn't like how it used to be, she talks and laughs with others like usual so am I. But it can't be like that anymore between us. Eventho we don't talk much she still remember her promise to me he bought me flip flop but still that doesn't change a thing, we still cold and awkward to each other what can I do?