Panic attack - not smoking myself though?

I occasionally used to smoke weed recreationally with absolutely no issues, starting about last year. At the end of last year I had a bad panic attack while high that lasted for hours, I’m almost certain it was laced with something honestly and thought I was going to die. I ended up falling asleep under the assumption that I wasn’t going to wake up, but hey ho. Tried to share a joint a couple times with my partner after that but no matter how little I smoked it’d happen every time so I stopped.

It’s been a few months since we last smoked - today I took a walk with him as he smoked a joint, I didn’t have any, came home and felt fine. Just came back from another walk and now I’m sat on the toilet, heart rate of 120BPM and feeling incredibly sick like I’ve had some myself but I haven’t at all! Why is this happening? I feel like I can’t calm down