I totally understand the worry when you notice a drop in intake, because I went through something similar with my second when she was on medication at that age and I kept second-guessing every feed. A friend of mine whose baby was also on omeprazole shared that once the reflux settled down, her little one became a much more efficient feeder and would simply stop when full rather than comfort-sucking through the discomfort. So the smiling and pushing out the teat could actually be a good sign that your LO is feeling more comfortable and is now feeding on her own cues. That said, since she is only 2 months old and intake can really matter at this stage, it would be good to bring her to see your PD just to confirm the amount is still enough for her weight and growth. You are doing great by paying such close attention to her, hang in there.