Unfortunately I'm having a similar experience with sativa. Amnesia Haze & other Haze is all that goes around where I'm from.
I've concluded it has to be some sort of physical effect mainly with the high THC sativa's. My sinuses will begin to close up, and I even find eating a tad more difficult as it feels like its pushing its way down through a smaller tube. This sounds like a sort of allergic reaction to me, which is a pity because I love the rushy head high and the creativity it brings.
My heart rate will increase noticeably which I can monitor with HR monitor which measures HRV (heart-rate variability) as well. My chest starts to feel tight and my HRV drops, indicating that my sympathetic nervous system is heavily in work.
Often I drop to the floor to do pushups and I notice that I actually feel stronger, which would make sense if my sympathetic nervous system was in slight overdrive.
Now what I've also noticed is that for moments I can get rid of this feeling by being fully present in the now such as by doing certain breathing exercises. When I'm outside walking or jogging, the feeling will pretty much go away entirely and I'll get into a more Zen like state. It's mainly when I'm sitting down trying to relax where this at its worst. This tells what I hypothesized for a while, and concluded for certainty after reading up about Wim Hof (The Iceman), that we can manually effect our own nervous system. I'd suggest giving him a Google if anyone is at doubts to whether or not it can be done, but I know it can.
I've started to react like this following an incident where I overdid it earlier in the year with a few unsavory party chemicals. Instead of resting the next day, I did a HUGE bong and went to the cinema and had a full on panic attack. Mentally I seemed fine, my thoughts weren't out of control, but physically my hands and arms started to seize up as blood diverted into my torso, creating a painful bending in my limbs. My hands and nose were ice-cold. It was a scary experience and was definitely the result of me not treating my body right for the few days prior.
So either these sativas are causing a slight allergic reaction now, perhaps in a nervous system memory response to that incident, or there are underlying emotions/issues causing this anxiety. But I absolutely put more weight into the former as I tend to meditate whilst stoned and really enjoy the process of listening to ones thoughts.
Anyway what I've stumbled across lately from measuring my HR and HRV is a website called HeartMath.org. (
http://heartmath.org/free-services/) Initially I discovered it trying to improve my athletic ability. Check the free-services part of the website. They go into detail about the state of Coherence, which I've really given heed to lately. They indicate how our emotions & thoughts, our nervous system, and respiration/heart-rate are all linked and in a lot of cases can be improved. They talk about heart-breathing and visualization as a way to relax once you feel any stressful or negative thoughts, nipping them in the bud. Anyone who practices meditation well already knows this I'm sure.
Having being doing this heart-breathing and a lot of intense physical exercise lately, I can actually
feel this state of coherence. I can nearly predict my HRV before I measure it (higher the better) just from how I feel.
So lately when I vape some Haze I can actually feel the coherence being disrupted, like the blood/air isn't getting to the right place hence the tightness. I find putting my hands up straight and stretched behind my neck helps resolve this, but I'd like to know for definite why it happens in the first place. Luckily it does not happen with Indicas and I hope to be getting some soon.
Hope I helped someone with this post, once you understand the state of coherence things will be a lot easier. Any anxious feelings, for me anyway, are PURELY derived from that lack of coherence. It makes sense when you think of it, if you're worried about your heart-rate or a tightness in your chest, your thought processes that follow aren't exactly going to be the calmest, most rational form of yourself.