Why Do I Have A Persistent Onion-like Body Odor And Altered Taste And Smell?

Hi,I am 18 years old and from past 1 month my body odor smells like onion specially underarms ,and even when I eat food it taste like that and also , when I smell any food it has strong smell of it .I went to see doctor, he told me to stay hydrated and I do that to but still, I can t see any changes and I can t even describe how i feel and nowadays when I smell that I feel like vomiting don t know what is wrong with me even black salt doesn t taste good to me