Acid reflux help!

My daughter is almost 3 weeks old and has been prescribed ZANTAC to help with acid reflux. Her crying has been blood curdling and I feel like I can’t do anything to soothe her. It’s the 3rd day of meds and she just ate and fell asleep for the first time in a long time! I could seriously ball my eyes out. Anyone else experience this or going through this? What kind of rocking or holding positions helped?