I think you might have scared him off. If he feels that you have overcrowded him with your 'calls and schedules' then he is probably backing off.
It is hard when you really like someone who doesn't respond, but I would tread very carefully with this one. Go easy and gently, be patient. Don't give him the feeling that you are stalking him. If you know of any clubs or hobbies that he likes then stick around these places or get the same interests. But don't hound him, act like you don't even see him and see if that stirs his interest.
But at the end of the day it might just be that although you like him, he may not have the same feelings for you. That is hard but unfortunately that is also life.