Why does nicotine cause me to have panic attacks the last few months?

For the past few months my panic attacks have been terrible especially after smoking weed or even a cigarette it was so bad to the point that I quit weed and even tried quitting smoking I switched to a vape witch causes my panic attacks to be a little less brutal but why all of a sudden is nicotine making me panic so much, I have always had panic attacks ever since I can remember probably have about 10 a day some lasting minutes some lasting hours, been having alot of troubles with my physcologists and physaciatrists they haven t helped me at all and its been five years since they started I smoked weed and tobacco for about 7 or 8 years but my brother passed away five years ago, can losing a loved one bring out panic and anxiety disorders this bad ? And nicotine is just stimulating me and making it worse ?