I took time because when it happened to me I thought nobody would believe me. I myself couldn't believe it was possible to have a bad trip with weed. So in the begining I felt very bad, thinking I had fucked my mind, wondering if i would be "normal" again one day. Not speaking about it just made it longer to understand the problem. I thought it was just a question of will or mind controle. I tried everything, but each time i smoke (only a few puffs) my pulse starts running faster. I keep calm, just smoke in relaxing situations, but nothing to do I get those ** tacchicardia crisis every time. So I came to a conclusion : that's like that, stop smoking it only make things worse. And then I began to feel better and better.
I still miss drugs (I always said I would never stop smoking weed unless I'm dead Bob Marley style) and maybe that's the reason I read sometimes on a forum like Bluelight

But I would be very happy if my experience could make you understand that what you are experiencing is not so terrible, that you shouldn't insist too long on weed if you get bad experiences each time, and that no your mind is not fucked up. It's not easy to adapt to a life without drugs, but in the end your mind will fully recover and you'll be able to live like anybody else.
And one last tip : be careful too with MDMA/XTC because you've experience tachiccardia with weed I let you imagine what it can be with XTC, even stronger crisis and way longer (sometimes 4 hours seem like an eternity).
Edit : I'm still wondering what caused all this mess too. I read sometimes that weed, psychedelics and bad trips can sometimes reveal schysophrenia, but I don't feel like that. The main issue is my heart racing very fast, arythmic too when i smoke but if i don't smoke i have no problem. I know the brain chemical is very fragile and maybe many abuses can change it a little. But I think that unconsciously your mind remembers the first bad trip and it's a way to prevent a new "chemical attack". Difficult to explain in english sorry.