Smelling things during sleep

Last night I woke up (at least I think I did) to this horrid,disgusting smell. It smelt like 1000 people farted in a small room. Nearly thought I was going to vomit. I woke up SO and said "wtf is that smell?!?" He replied, "what are you talking about? I don't smell anything". I was up for at least 20 minutes smelling it. I guess it was all in my head, but this has never happened before. Could this be a sign of pregnancy? I'm 6dpo