Julie, I had a small bowel resection in 1978, enjoyed a 20 year remission before it returned. Fortunately the Crohn's has not been as aggressive since its return. However, I do have a high grade partial obstruction at the old resection site that will have to be dealt w/eventually.
I did suffer w/small bowel bacterial overgrowth for quite some time. And, yes, the symptoms were bloating and nausea. Dr May, from CCFA's now defunct Ask the Specialist forum, first suggested the possibility of bacterial overgrowth and antibiotics for it. Cleveland Clinic also suggested antibiotics. I was on ampicillin the first 10 days of every month followed by tetracycline the first 10 days of alternating months for about a year. I also took a good mixed probiotic 15 days out of every month (Enterobiotic was the brand my pharmacist recommended). It no time I could tell just by symptoms when I was due for the tet or ampicillin and it was longer period of time between alternating them.
Now, some crohnies do NOT do well w/antibiotics. I've always responded well to them. But then when we considered which antibiotics to use we opted to use some of the older antibiotics that weren't quite so broad spectrum. This was BEFORE Xifaxan was approved. Certainly Xifaxan would be a good choice today.
Also, I could tell my gut was responding to the alternating antibiotics w/in just a few days, definitely w/in the first 5 days. And I could tell when I was due for them to by the return of some queasies, nausea or bloating.