The first question is, what recipe/type of ale are you making? Depending on the type of yeast, style, etc, the time to being done will vary alot. Having said that, 8 days is way too short a time. The beer is definitely green and will change over time. I now leave everything in primary at least two weeks to be sure the yeast finishes it's work. Some people on this forum just leave everything in primary, but I like to go to secondary for another 2-3 weeks or longer depending on the gravity and style. You'll keep hearing to have patience, but it's true that time is good to beer.