Also hoping you move towards recovery and it sounds like you have good people in your life to support that.

I would say that a festival (even small and friendly) is possibly not the ideal place to take psychedelics, unless you're very experienced. If you are particularly prone to paranoia, it can surface with psychedelics (even Cannabis) even in good settings.

I suffer from diagnosed generalised anxiety disorder (GAD). Weirdly that second trip was actually much more relaxed and enjoyable during the trip than the first alone with just my wife on the canal boat, even if I did almost pass out at the start.

Thinking back, your experience of the seizure thing sounds similar to what a friend of mine experienced, not with LSD but MDMA. It is possibly related to the motion sickness and brain poisoning reflex.[0]

[0] https://en.wikipedia.org/wiki/Motion_sickness#Defense_agains...

This is what it made me think of as well. My first experience with MDMA started out in the grips of anxiety, trembling and feeling multiple uncomfortable symptoms, afraid I had taken too much. I don't think I was able to even stand or walk for several long minutes.

I went on to have a wonderful & memorable experience, feeling closeness & positivity with every human interaction for hours. The worst part after I got over the initial freakout was coming back down. I've heard people talk about such early-stage freakouts happening on other psychedelics, too, but I don't have much experience there.

Serotonin is involved in regulating the digestive system so if you take drugs that act on serotonin like LSD or MDMA symptoms like nausea are quite common.

I did experience motion sickness on LSD so could be related