My fist anxiety attack ever was after smoking weed. That being said, cannabis did not cause my anxiety- rather it made me much more introspective and aware of my pre-existing anxiety. I imagine you're experiencing fears of losing control or dying, perhaps at times feeling as though you're being smothered or that you're detached from your body. This is known as the 'fight or flight' response, a defense mechanism triggered by a perceived threat, even when there may indeed be no threat present. This response is triggered by your sympathetic nervous system, which releases an massive amount of epinephrine which your brain is providing to help aid you in a potentially life or death scenario. So essentially, your brain is inappropriately releasing adrenaline and the stimuli appears to be cannabis. In order to stifle this, you must understand the nature of your own anxiety. Do you struggle with existential anxiety, perhaps a fear of losing control? It's imperative that you address your anxiety head on and do not attribute it to cannabis, or else you will always have anxiety after smoking it. Reaching this catharsis may indeed be a lengthy and arduous endeavor, so I recommend you research some breathing techniques to aid you in periods of high anxiety. I've had anxiety for well over a decade and I am now free of panic attacks and medication. At one point I thought I would never be able to smoke again, but now I frequently enjoy it again. It can be done, but you must be willing to literally tame your own brain. Sorry if this was lengthy, but this is a subject rather personal to me and I 100% empathize with you. You're not in this alone!