I have experienced the same issue and have been workin it for the last 2 years. As A kid, I smoked everyday, all day. Wake and Bake was my norm. Several ounces a week was easy. I smoked everyday for maybe 9-10 years? I quit for 10 years or so? Then tried to go back. Everytime, I had joint or bong hit I'd get racy pulse, feeling like I was having a heart attack although if I looked close I was only "feeling" like that, it wasnt reality. My pulse was fine. After reading all I could it seems to be in the anxiety attack area. I have no life issues. I'm not particularly anxious about things in general, I own my own home so surroundings are not it. I am an older guy just looking to smoke a bowl on occasion. I have tried 10-15 different varieties all with essentially the same results (even the magic Strawberry cough). What I have concluded from reading the different online resources is my body must have developed an "allergic" type reaction. For some mysterious reason this can happen as we age and not with just pot. I can eat cookies and as long as I am careful I seem to tolerate that. One bong hit can set me off. Even though the symptoms are "fake" They are uncomfortable so I have 2 choices, stop or just be real careful. I am going to continue to try different varieties. Sure it's sad, but we cant fight mother nature. Maybe your problem is different. I fought believing that I had developed this allergic thing for a long time. Most comments say, its your surroundings, your mental state, too strong, just think uhmmmmmmmmm and it will all be fine..I only wish it were that simple. Just my 2 cents. Maybe after it is decriminalized someone will be able to do a study on this and get to the roots on whats the real issue is. Until then, cookies are the way to go for me....
Good Luck in your travels.