Blood?

My LO got prescribed a reflux med - we decided to start it Sunday instead of trying hypoallergenic formula first (bad acid reflux) first dose Sunday, after her second dose on Monday we waited the 30 min to feed her and in her spit up we noticed a red tinge … blood? Called GI , no one called me back, it didn’t happen again that day or yesterday - then today after her meds we fed her 45 min later and I noticed more - except this time it’s definitely not AS noticeable or as much.

First pic is Monday , second pic is today

Anyone else had this happen?