Dating my best friend, but...?

Okay, so I know this guy, we were really good friends and we used to be able to talk about anything, make each other laugh for hours on end and it was really fun. I don't know, I think I've always liked him secretly and I think he liked me, a few days ago he confessed that he was in love with me, so we somehow started dating. But now he acts really weird around me, all we do is say things like, 'You're so cute' or 'I love you' or something and although I do mean it, it's really weird for me, since I just want to be able to talk to him like before again. I don't know how to tell him this without sounding like I don't appreciate him or I'm selfish or anything. Help?