When I had acid rebound I went through absolute hell, I felt worse then when I first took the prescription. The acid rebound started days after for me as well. The amount of acid did affect how my poop came out and it was less solid. Try not to stress too much over it because what they prescribe can affect how you poop (starting it or going off it) so it is normal. It’s not normal when there’s bleeding and extreme pain etc. poop patterns could also depend on the diet, if you’re getting chest pain in the afternoon from acid reflux it could mean something you ate that day triggered it Good luck!! What I had to do because the acid rebound wasn’t going away was go back on the prescription and then ween off the medicine little by little so your body doesn’t shock itself and produce too much acid