Hi there,
Passing gas vaginally is a sure sign of a fistula/abscess. If you look at the bright side at least remicade will help fix this right up. I hope your GI sends you for an MRI with the dye as that is what I always have done to find these nasty things.
As another long term crohns patient I get that it gets old fast, but hang in there things will improve.
Julia