Hello Welcome to HCM Tobacco consists of nicotine. Nicotine is an activating substance and it cause activation of brain areas. You are having intense anxiety attacks and you have habit of chewing tobacco. Most likely nicotine is the substance that is aggravating your anxiety symptoms and is causing significant impairment in your functioning. Try to decrease the nicotine use gradually over time your anxiety will improve. As nicotine is very addictive substance you can consult a Psychiatrist for deaddiction. Many medicines like bupropion, buspirone etc are used in nicotine addiction to decrease anxiety and to decrease craving of tobacco. Try relaxation exercises and yoga to keep yourself relaxed. Hope this helps you, thanks.