Possible seizure during a trip 1.6g jack frost

After about half an hour we toke a walk into the bush and started to get vividness of colour's and and slight distortions. 

After a full hour I had euphoria feeling throughout the body and distortions and wavyness of visuals. 

These effects continued through out the evening. 

About 5 hours after taking the first tea I made a 2nd tea of the same dose of 0.8 of jack frost. 

The visuals increased and everything in the trip was going very well and felt super comforting. 

During the night I had had 4 ciders and a few puffs on a joint. 

At around 3 hours after having the 2nd tea I had another puff on a joint mixed with tabacoo. 

15mins afterwards with no prior feelings of uneasyness I started to get light headed and my eyes rolled into the back of my head and I collapsed with lockjaw. 

During this time I had intense visuals and saw a tunnel of my friends checking up on me which drewe back into reality.(I was gone for 30 seconds) 

I came back with a clear mind and no change to the level. Of my trip before this happened. As I was sitting there my eyes would roll back and snap back when people would talk to me. 

At this time I had a very high temperature and sweat pouring off my face. 

My friends moved away from the fire and as I was on my way to lie down I went out again with the same eyes rolling into the back of my head and heavy visual hallucinations. This time I was out for 1 minute. 

Again as I came to reality I snapped back to the same level of tripping as I was before this event. 

After some chocolate and water I started to get cold and decided to go lie down in my tent. 

While lieing down I was back to being coherent and tripping but no elevated levels from what I was before the event. 

I stated to have body shakes that were uncontrollable for about 30 minutes coming and going and finally they stopped and I was left lieing there having beautiful eye closed 3d visuals and no adverse effects. 

All in all 99% of my trip was amazing but am curious to hear if anyone else has had anything like this before. 

I have been taking psychodelics for 10 years and have alot of experience with tripping and have never had or seen anyone have this reaction. 

Any insight into what may have caused this would be much appreciated. Only thing I can put it down to is a drug induced seizure 

I have never had any problems with seizures before. 

Thank you for any help!!