I have a daughter who has severe reflux and I can tell you that chamomile tea did nothing. I tried pretty much everything out there and the only things that worked for us:
1. Cutting all dairy out of my diet while breastfeeding. I think I read that 80% of all infants with reflux also have a dairy sensitivity. The fact that your daughter is also gassy points to a sensitivity of some kind. Try cutting out all dairy (milk, cheese, yogurt, ice cream, sour cream, etc.) for several weeks and see if it helps.
2. Always having her sleep on an incline. That meant raising the head of her crib by 8" and never lying her down flat. Ever. Also, keeping her upright for 45 minutes after eating.
3. A pediatric chiropractor. My daughter went for alignments every few weeks for about six months and the difference was amazing.
Zantac didn't work, Prevacid didn't work, Prilosec looked like it was going to work, but then didn't. Chamomile tea didn't work. I never tried fennel tea so can't comment on that one.