Now that you've said it.. I think it's best to not say it again until he does. He's informed of your feelings and doesn't need to feel pressured to say it in return. He needs time to develop these feelings and be sure of them... saying "I love you" constantly will just make him feel pressured. If he really does love you... he will say so... but only after he is absolutely sure of his feelings...
"The weakest soul, knowing its own weakness, and believing this truth that strength can only be developed by effort and practice, will, thus believing, at once begin to exert itself, and, adding effort to effort, patience to patience, and strength to strength, will never cease to develop, and will at last grow divinely strong."
- James Allen