I go through phases. I can drink a fair amount sometimes and get pretty wasted; sometimes I can plow through endless alcohol and still function; barely having a hangover the next day. It's like my tolerance changes monthly.
My big problem I found out is when I mix waaaay too many different kinds of alcohol. One night it was a mixture of mixed drinks(red deaths, vampires, drinks with a lot of ingredients of all types), Jagermeister(lots count of how many shots), whiskey and a bunch of hot wings. To top it all off, I had very little water that day on top of it. Needless to say that night I broke my record for never getting sick.(Still the only time tho.) I was collapsed on a street corner for awhile. Now, I will only mix certain things I know I can get away with (JD, Jager, and beer for example). Otherwise I try to stick to one thing.