Carl, without sounding indelicate... erm..
Had you showered yet? Hear me out!!!
Lexy went ballistic with my ex when he had been out messing with his car engine, and came in... she refused to go near him. He had to have a shower first to get rid of whatever scent she could smell (honestly, he didn't..) and only when he did would she go near him again.
Maybe Bilbo smells a scent of some kind on your clothes, shoes, etc that you have picked up outside?
Sorry, didn't mean to imply you smelled
I know you don't