Was it in the moment or is he serious??

I've been having a secret relationship with a guy. I met him last year and we grew really close within the past year. We hooked up back in June but I stopped seeing him over the summer. I recently started talking with him again. We slept together again this week. But while we were having sex I swear I heard him say "I love you". I was so surprised, that I said "wait what? You love me?" And he tried to play it off like "No, I said how did that make you feel." I was so freaked out! It wouldn't be so bad if those two sentences sounded similar, but they don't, at ALL. And now I'm confused. Was that in the moment, or was he for real? I feel like if it was in the moment he wouldn't have tried to play it off. I have no idea what to do.