Not what I expected

Riley had her follow up appointment today with her pediatrician. Her throwing up has decreased, though she still has some throw up days. She has been eating well and besides a little cold seems to be much better.
Well, I went into the doctors office and placed naked Riley on the scale and I did not see what I had hoped for. She has lost 4.5 ounces since her last appointment on Sept. 18th. I tried to hold it together the best I could, but my stomach was upset and my eyes were quickly tearing up. She has now fallen off of the growth charts and the doctor is concerned, of course.
Where do we go from here???
She now has to take Pepcid for 2 weeks in hopes that it will help. She was taken off of Zantac because she could not tolerate it so I hope this will be better for her. I do not know the reason why or how this med is going to help her, but we will start it tonight and hope it does something. We are scheduled to go back in another 2 weeks to check her weight and come up with a new plan. Hopefully, she will gain weight and there will be no futher action needed.
Please pray for her and her little body to respond. Pray also for me as I am now getting sick and continue to have great fear for my little baby. Every time I put her to sleep I fear she will not wake up. This of course has been very emotionally draining and I really need to have my heart and mind put at ease.