I Smell A Metallic Or Burning Smell Randomly. Sometimes It

I smell a metallic or burning smell randomly. Sometimes it seems like it's the irony smell of blood. Every once and a while it's a wierd moldy rotten smell or a sharp sulphury odor. But no one else smells them. I usually smell it for no longer than a minute and even then it comes and goes and does not seem localized to one location. Usually the smell lasts for seconds and then is gone. I smell them in the car, at home, sometimes at work.
I often have a more serious smelling spat in the morning, either just as I'm getting up or shortly after. What the heck is going on???