What can lead to anxiety disorders? .. and does depersonilization cause people to not recognize themselves?

If a person has had no tramatic event or life changing events why he/shesuddenly develops an anxiety disroder ( panic disorder) and it doesnt run in the family ? i havent had any tramatic event however i do have anemia due to lack of vitamin b-12 , folic acid and protein ( im a vegetarian) which i know can lead to anxiety and also ovarian cysts and thyroiditis , im also overweight . However now ive developed depersonalization which is on my mind 24/7 and for the past week ive felt as if i dont know who i am and as if i dont recognize myself in the mirror although i know its me . Is it curable? Is it due to my other sicknesses?