The L Word

Has anyone ever said “I love you” to their partner and they didn’t say it back but eventually said it? I’ve been with my boyfriend for 5 months (I know it’s not that long, but I know beyond a shadow of a doubt that I love him). I stayed the night at his house Friday night and left Saturday afternoon. I told him Saturday as I was leaving (it just slipped out- I had been holding it in for a few weeks) that I fell in love with him. He smiled and he hugged and kissed me goodbye and about 15 minutes later he sent me a smiley face in a message. We haven’t talked much since then which isn’t necessarily abnormal because he hardly has his phone on him but part of me wonders if it’s because I told him I love him. His actions say he loves me and I was sure he’d say it back when I told him. Advice?