Not sure if this is needed but just to be mindful: 
Trigger warning for Marijuana 

About a month ago I took an edible(legal in my state) and it gave me one of the worst panic attacks of my life. It gave me an extremely fast heart beat (common negative side effect) that no breathing exercises could calm down. It wasn't a totally terrible experience, I actually had a lot of fun once I calmed down after about an hour, but for the sake of my mental health I haven't taken one since. I did, however, smoke a couple times after that with some friends and wound up having the same issue. I never had that feeling with smoking before or any anxiety at all so I'm pretty frustrated but whatever I never really cared to smoke in the first place so I don't mind avoiding it. Problem is, every once in a while now I feel overly conscious of my heart beating in my chest and I can't get my mind off it. It's not that fast or anything, unless I start feeling anxious over it. It's honestly really starting to stress me out because it reminds me of how freaked out I was when I was high. Not the worst thing in the world to be anxious about I guess but I'm tired of tormented over every little thing. If it's not this then its some other random little thing. Like why does my side hurt? Why does my jaw hurt? Are my teeth supposed to feel this way? Yada yada and its like great another thing that makes me panic for no reason I really needed that. Wish I could catch a break man :/