How much damage does one year of drinking do?

Ive been drinking for about a year now, and I'm 19. I don't drink that much, to be honest, maybe at most 2 times a week to start out with. But when I did drink I would often reach or go in excess of 8 drinks a week. There have been two periods in this year, 2 months long each where I haven't drunk at all due to extenuating circumstances. The past six months I haven't drunk nearly as much as I did since August of last year. However, in this year of drinking, I've had at least three nights of blackout or almost blackout memory loss and two days after which really bad hangovers occurred, including vomiting, etc. How much brain/liver damage has this caused?