Cannabis has caused anxiety in me before, but I had anxiety problems prior fwiw. In a weird way, I kind of used the anxiety from Cannabis as "training."
What I mean, is that when I would get anxious from cannabis, I would try and talk myself down, remind myself that nothing bad was going to happen, and then kind of intentionally try to refrain my thoughts in order to force myself to enjoy the experience.
I learned that the more I did this, the better I was at being able to do this in other situations where I would be inappropriately anxious about something (even without Cannabis).
It's not perfect, but has seemed to work better than anything else I have tried. So, my point is that I learned the only way I can apparently beat anxiety is to charge it head on.