Too much nicotine, too much CO2 in too short of a time (even if spread out) - basically TOO MUCH SMOKING
Just remember - everything in moderation. A 2-3hr session is ok (once and awhile), but (4) 1.5hr sessions, specially with 2 of the tobacco's being Nakhla, is probably alittle too much, even for the most hard core smokers.
If you try it again, eat WHILE smoking (slows you down and helps w/ the nicotine absorption), make sure you drink tons (try some Gatoraid/Poweraid instead of just plain water/tea) and remember - you need AIR. Take longer brakes.
Trust me - I've done this ONCE and learned the HARD way - LOL. Even during the LONG lounge session, I wasn't the only one smoking and eat/drank stuff. But I still had a bit of a headache afterwards. LOL!