What is wrong with me?

I have been there and i seriously suggest you go and talk to a doctor or councellor about how you feel to isolate the problem. I too had a panic attack from cannabis a year ago, and have been battling anxiety ever since I stopped smoking, mainly due to my mind not being disracted by being stoned all the time now. All I can say is for the first few months after my one and only panic I felt like I was dying everyday. Councelling antidepressants, constant activity and regular trips to the doctor have helped me a lot, still got a way to go yet though I find these feelings do come back around, and if you let things be then your anxiety will trigger a deep depression as it has for me. and good luck