Me & my boyfriend broke up 5 months ago, i still think about him, why? If itz been a while ago?

We go to school together & hes a senior so itz better cuz hes graduating this week....im kinda glad hes leaving already cuz i dont hae to see him no more but at the same im pretty sad....i was the type of girl that wasnt too affectionate with him but he was, but later on i did....when we broke up i didnt cry cuz im not that girl that cries especially for a guy but im pretty sure he did....im just confused cuz itz been 5 months & i always think about him, like any little thing remembers me of him