Unforunately, we haven't had much luck with the SIBO stuff either. It's so frustrating.
Our GI would only do one round of Flagyl. It helped...but I don't think it totally got rid of it. She even did a repeat Endoscopy (to confirm celiac disease because of inconclusive results before) and they did an intestinal aspirate (tested the fluid in the intestine...
I have low hopes the OP will see this, but did you ever get results back? My daughter is getting breath tested in 2 weeks and I highly suspect SIBO. Her symptoms are exactly the same.