Lol, 5 beers isn't generally enough to be a problem. Well, unless I'm basically chugging them back the whole damn time. Then it can be a problem (I posted somewhere about learning that 3 beers, in a very short period of time, is enough to make me sick, by virtue of not having enough time to settle and digest, lol).
My other record for getting sick on beer was something like 7 beers in 2-2.5 hours. Online calculators estimate my BAC should be somewhere between .125 and .165... I'd say that getting sick at that level isn't much of a surprise...
Mind you, the last st pattys day I drank with my friend richard, I had 7 pints, which is equal to 9.33 12 oz cans of beer... I dunno how long I was drinking for, but at 2.5 hours, i'd be at .220 and at 3.5 hours I'd be at .206 according to one of the calculators, so I was definitely drunker that night (I did get sick... I just came back and kept drinking, lol)... Even funnier, my friend mike and I killed a 24 of beer in 6 hours, ish. I should have been at .196.... I was sober.