I read that you keep blaming the gin cause you never had it before even though you know it could be something else. I just wanted to tell you that I understand perfectly what you mean. When I got food poisoning when I was a kid, I blamed it on the cocunut cookies that I was eating right before my symptoms started. But I know it was caused by a sandwich I ate at one of those small square food places stuck in the middle of the isle at the malls, cause it was the only thing that I ate that no one else in my family ate....everyone ate those cocunut cookies. To this day, cocunut cream pies etc kind of gross me out even though I know that those cocunut cookies were not what caused my sickness.
It really is unlikely that some gin caused your illness, more likely sushi, or just a buildup of constant bad living choices.