Hallucinations are fairly normal for human beings. Don't be worried. Oh and if all you were drinking was alcohol over those 5 or 6 hours you'd be very dehydrated from the sickness + alcohol. So you wouldn't feel it but you'd be drunker than you think. Especially if you didn't eat during that time.
There's a reason why they say drink plenty of fluids when you're sick. And they don't mean alcohol
I mostly have auditory hallucinations personally (short ones, calling my name, etc.)