Acid Reflux

The doctor just switched my baby from Zantac to Omeprazole. Has anyone had any experience with this? The Zantac was working beautifully for a while, but called to increase the dose (she's been growing like crazy- up 2 sizes since being put on it) and they switched her. I know it can take a while to work, so I'm looking for success stories as motivation. My once sleeping through the night (8 hours) baby is now waking constantly.