Pharmacology - Spins and Nausea: What's causing this?

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Swim has been smoking for about three months now. Swim has enjoyed it but he's starting to get problems.

Lately when he smokes he has a great time for about an hour and a half. But after that he gets bad spins and usually passes out and wakes up an hour or two later. The spins have been getting worse so far everytime he smokes.

So what could be causing this? Swim thinks it might be one of the following.

1.He doesn't have a piece yet so he's been using a waterfall with the bowl made out of a socket head (cleaned of course.)

He's smoked out of proper pieces of friends as well and has gotten the spins but not nearly as bad as when he uses the waterfall.

When he lights the bowl, as far as he can tell, it's not melting the plastic on the bottle he's using.

2. He tries to clear the bottle in one hit which is probably more then he can handle and isn't getting enough air.

Can you guys help swim out and figure out what's causing this? He wants to smoke again but gets nauseous just thinking about it.Help much appreciated.