Has this ever happened to you?

Okay. So me and my girlfriend have been dating for like 2 and 1/2 months now... and I really really like her... but lately it just feels like maybe we're not meant to be. Like, I've been feeling far away from her except when we're together, when before I felt really close to her no matter where I was... Idk what's causing it I mean I still like her, but for some reasons some of the things that seemed cute before now I just don't think anything special about them... I don't want us to break up so soon but is that what it's heading towards?? I still want to be with her it's just for some reason I don't think I should... And I know we prolly weren't gunna last past high school but it's just too soon I think... it could be cuz we haven't spent much time together lately but yeah... if you need info filled in to answer better please say so I will add as you recommend.