I am 31 and have been I must admit drinking for enjoyment maybe once a
week for many years (on and off, it's not like every week for 10
years).  I used to be able to drink all night, on some occasions not
only get drunk but sustain the drunkness by having one or so an hour.
The next morning I would feel headache-y and hungover yes, but rarely
physically sick in the stomach.

But for the last year it has gotten ridiculous- if I go to bed at say
3am I wake up at 6 or 7 feeling sick, and often later that morning too
if I get back to sleep, every time I get even mildly drunk.

Occasionally I throw up but usually sit around feeling not quite bad
enough to vomit but way too bad to try to lie down & sleep.  A shower
may sober me up a bit but usually it's hours of sitting around
watching rubbish tv.  It seemed to happen all of a sudden about a year
ago, after I got some strong bourbon duty free and drank that. I
thought it was the strong spirits (instead of my usual beer to start
things off) but it happens all the time now.

On the weekend I had 5 beers + 1 vodka over 6 hours and woke up
feeling sick.  Any 50 year old can do this without feeling sick so I
do suspect it's more than simply "you are getting old".

Is there any problem?  Should I eat more, take certain vitamins, do a
detox session to clear my liver out?  Should I give up alcohol for a
while to clear out my system? Or should I even drink more to make my
body more used to it?  (note I drink absolutely nothing dring the
week). Yes I do drink much water/gatorade before bed and during the
night but it has not much effect.  Any help would be nicely
appreciated!  I can give it a go.