look, im not medical expert for psychoactive chemicals,but i think the major cause for anxiety is from guilty feeling, couse marijuana is illegal in most of countries.. it's feeling from deep inside of peoples mind. its not your fault because that.. thats just a subcommittees feeling. its a many reasons why somebodys have a feeling of guilty and in finaly instance - panic attack, like sexual behavior etc. but that attack is not punishment. its just very bad feeling. i battle with attacks for some years.. but i spoke to myself; its ok. you are good man.. you didnt anything wrong. that is just bad trip..
it sounds like you had some anxiety that was already there and brought to the surface by the smoking. I don't think the smoking 3 times has given you a panic disorder, some people can't tolerate pot......i wouldn't worry about the smoking but rather seek counseling for your anxiety problems.
Make sure it isn't laced weed and make sure you find out it is, I've smoked and still do smoke weed PLENTY of times and ALWAYS was scared of my parents finding out or smelling it on me and i still am. Towards my experience you're just getting to scared and thinking about it, which anxiety causes your body to think symptoms are really happening but their not, just try to relax or speak to a therapist.
Just take your mind off it; if you're sure it's not laced, then you'll be fine.