Slept with a friend

Ok so here's the deal: Ι've been 'friends' with this guy for almost 2 months and we really mutually like each other and see each other quite often. The truth is I dont actually see him as a friend, I am in love with him -and he feels things for me as well, Im not stupid, I can tell he is attracted to me, even if he sometimes tries to hide it. Anyway, last week we ended up sleeping together and it was great. But we mutually agreed (before having sex) that we would not go into a relationship and stay friends, so he most definitely didn't try to fool me into bed or anything like that. He even said that he respects me a lot and would not want to destroy any relationship we have. Now, a week later, his behaviour towards me is as open and gentelmanly as it was before we made love, as if nothing happened, but at the same time I can see that he becomes a bit shy with me sometimes, or other times even stares at me for a long time. It seriously reminds me of the film 'When Harry met Sally', Im not joking. The problem is that I made a mistake when I agreed that we would sleep together only once. I want to tell him that I want something more and let him know that I have stronger feelings for him, because he most likely thinks that I dont (right?). But Im afraid I will scare him away. Do you think he feels the same way? Is it too late to tell him how I feel after what happened?