This could be a real case of psychosomatic disorder.
You believed it so hard that you managed to make your body chemically cause body odour.
My psychiatrist thinks that is the cause of my BO, specially because I had a BO experience (just armpit sweat) 1 year before my actual BO started and it was so embarrassing I couldn´t stop thinking about it...
it´s almost like my worst fear came true. And my BO also triggers so badly when I´m nervous and arouund people I don´t wanna be around...
So according to my doctor, it´s like my mind caused a "skunk effect".
Think positive, see a therapist... it may not have started on your mind, but it definitely plays a big role on it.