Welcome to HCM
We understand your concerns
I went through your problem description. From the description, it is clear that you have hallucinations
/ delusions which are mental disorders and need to be treated by a psychiatrist. But nothing to worry. There are treatments available and these can be cured.
For the time being, learn to ignore the odor of gasoline / diesel which is emitting from your body. As no other person can smell or feel it, believe that it is fake and you are imagining it and worrying unnecessarily. Stop taking note of that smell and eventually it should go off. Do consult a psychiatrist
Hope this clears your doubt. Available for further clarifications.