It may not be bad to give him a week or so, then to send another e-mail if you don’t hear anything back. Presumably (at least one would hope) these vocations directors are busy. I know from talking with the vocations director of my diocese, it often takes days to a week or so for him to get back to me. (Though I would imagine that with something urgent he would probably respond sooner.) On the other hand, I can be pretty slow to respond to e-mails myself.
Boso, as far as telling your parents, eventually you will need to. It was hard for me to approach my dad and explain that I felt a calling to the priesthood. He is a non-practicing Protestant who was raised in a very Fundamentalist church, so I had no clue as to how he would react. The only advice that I can give you is that if you think your parents will react adversely, is to pray that they too will be open to whatever God has called you to; although they may not be thrilled with it initially, ultimately, they want you to be happy.
Between the time that I mentioned to my mom that I was discerning and when I mentioned it to my dad (about a month later), the thought crossed his mind that the priesthood might be something I was considering, and he came to a peace about it (even if at that point it was an uneasy one). When I finally told him, it was his lack of strong reaction that left me being most surprised. In the past three years he has slowly warmed up to the idea a little more, but has always encouraged me to not shut out considering marriage as well, and his doing so has helped me to not move too hastily. I hope to be accepted as a diocesan seminarian sometime this school year (I’m now a senior in college). Ultimately if you do get resistance, prayer and patience are of utmost importance.
I hope this was at least somewhat helpful.