Once I mixed dxm, vodka, ritalin, ativan, and pot. We were chilling at a friend's place, and these people didn't know I had consumed that many drugs. We were smoking, and suddenly my heart started beating at least 170bpm and my vision and hearing turned into a strobe light, everything I heard seemed far away. I stumbled to the door and sat outside, not replying to my friends for like an hour. Then my friend had to drive me halfway home in my car with her boyfriend following her, and I drove the rest of the way home. I was fucked up for awhile. Everytime I smoked weed after that the strobe light thing happened again where my heart raced, my vision and hearing seemed like a strobe light. In and out. I quit smoking for several months and the second time I smoked after that, it started to happen but I forced myself to believe that it was my body going back to that experience and that it was just a natural reaction, that I could re train my body not to react that way. Luckily I had some ativan to prevent a major freak out. Now when I smoke as long as I don't get too high, keep myself calm, I'm ok.
So yeah, I've had pretty bad anxiety from weed.