Vomiting + Paranoia on Ecstasy (NOT Coming up Nausea)

[Conkermon]

SWIM has been taking ecstasy for 2 years. On many, many occasions SWIM has had periods whilst on E, of feeling terrible (he refers to them as "bad spots"). These "bad spots" would typically last only for a couple of minutes on an otherwise awesome night where he feels the charecteristic loved up feeling. He also only gets these periods some time into his roll (he doubts he is coming down as it is sometimes during a peak). If SWIM is unable to console himself and convince himself that there is no reason to feel bad, then he will sometimes feel terrible for the rest of the night and be unable to enjoy himself.

Alongside this, SWIM often vomits whilst on E, this comes along with the paranoia/"bad spots" and perhaps could be a result of it? It must be noted that SWIM does not get feel nervous before taking E like some people do, so i don't think that is what causes the sickness. SWIM is not on any other medication and takes E on it's own without mixing with other drugs. He doesn't drink alcohol but he does drink water. His friends who take the same E are almost never sick, although they do sometimes have "bad spots." Does anyone have any possible reasons as to why SWIM experiences these adverse effects of sickness and paranoia? You might ask why SWIM bothers taking E if he gets this kinda reaction to it, but he says that he has such a good time before he begins to feel paranoid and is sick that it is worth it, and although he often feels like this, he sometimes doesn't so he thinks it's a risk worth taking.

Any feedback would be greatly appreciated, although SWIM has been dropping for 2 years, something is clearly not right here so he feels it is about time he asked the pro's.