Is it normal if im obsessed with someone i don't even know that well

It is helarious! lol i even laugh at myself but whatever =P So i met this guy a few months ago and ive known him for quite a while but the last time we hung out we got closer and i got to know him better. I always thought he was cute but never liked him he was just there. Finally when he came to visit in california, we hung out with friends and we got on another level. We flirted here and there, and feelings developed. I developed a crush for the whole time he was here however, for the rest of the time he was here it didnt go as smooth as the first night and made me depressed. But i still managed to have this HUGE crush on him even though i do not really know the guy. Or atleast i dont know the guy as much as i picture in my head. In other words, when i get excited about a guy i start making plans and daydreaming about him. I realized recently, daydreaming is only of who i wanted him to be not who he probably was. So hes gone now but i am left with this HUGE crush on him, a guy that i imagine in my mind not the guy who he probably is. I still like from what i know of him of coarse but i plan too much because i get excited. Is it normal that i have this HUGE crush on this guy and i dont even know him that well but still get happy when i think of him? Does anyone else have similar experiences?