I think I accidentally rejected him?

My guy friend and I were walking through the halls at our school and we ran into one of his clmates. People have told us we make a good couple and apparently we act like a couple. Most of our mutual friends seem to think he likes me, they say the way he acts around me and the things he does shows that he likes me. Our friends often joke about "what we are doing" when we are running late but are together before we get together with the rest of our friends. We do many things that apparently are "couple-y" like talking on the phone for 6 hours at a time, or a few nights ago he was over waiting for a ride home and we fell asleep watching a movie and when we woke up we just lay there and talked for a few hours. I see this as just really good friends, but everyone else sees these things as we like each other. When we ran into his clmate/friend she said "oh! Is this your girlfriend?!". He didn't say anything so I reacted quickly and said no. When I said that he started to rumage through his bag. I'm worried he may actually have feelings for me and I rejected him by my fast and "defined" no. If he does like me I would like to know, but I'm worried this may have deterred him from telling me. If he does like me, would my quick reaction seem like a rejection to him?