My 6 month old sleeps 1-3 hours and wakes up crying. I have to hold her upright to sleep. We tried gas drops, gripe water, now chamomille tea. Now what?

Check her ears. "jack-in-the-box" syndrome is often seen in kids w/ ear infection or ear pain. After being down for 90min, they pop up screaming. Then ear pressure is reduced & they return to sleep only to repeat the cycle all night or w/each nap. Reflux is certainly also possible for the same reason. Pressure in the head and stomach build when lying flat. Check in with your pediatrician.
Pediatrician. Sounds a lot like reflux. I'm guessing this has been going on for awhile. The gripe water and gas drops are a good start, but the acid is likely hurting her esophagus, and keeping her upright allows the stomach to empty faster, limiting reflux. An antacid like Zantac (ranitidine) is the first drug of choice, and often does a lot of good. If that's not helpful, follow up with a gastroenterologist.