Guys,some help please...and girls are welcome too!thanks=]!?

ok,so i have been emailing my bf for awhile...and suddenly after a few emails which the last one he ended with a really nice sentence saying he miss me and all but now he didn't reply my last email for 3 days and its like he's been waiting for me to sign in on msn so we can talk but i said bye bye and then a long see u later,even tho he said cya and hopefully its soon,i know he wants me to talk to him so did he not reply cause he's tired of me running away from him even if i do it teasingly or...something else?thanks for reading and answering,really appreciate all ur answers