What are the positive effects of quitting smoking?

I have purchased the perscription Chantix and am now on my way to a smoke-free life. I have been noticing some things that make me (my body) feel different after not smoking for a few days. For example, I feel like I have more energy...is this from quitting? Will I notice more things like this as i continue? Or was this just nervous energy and all of this is this just in my head?