nukka
Bluelighter
There is no such thing as un-cut heroin in the US, if for no reason other than safety. Dealers don't want their customers dropping like flies.
Indifference said:H isn't my drug at all, so I could be way off here, but what you described sounds like a pretty generic whitey/panic attack.
You must have pulled a whitey before, when you drink too much (alcohol) and smoke too much, your vision goes black and white/fuzzy, you feel sick, the room's spinning, you sit still and start feeling better, go to move your head and it all comes back again.
Makes sense with the ice cream too - whitey's are often associated with low blood-sugar levels. Had you eaten anything earlier in the day, or had you drunk any alcohol?
If you hadn't eaten anything, or had drunk a bit, I'd bet it was just a whitey. As I said though, H isn't my game, so I'm just going on extensive cannabis knowledge.
Hope this helps.