Severe constipation

Hi Girls
My 21 month old has been struggling with constipation for about a month now! The doctors put him on cosmocol paediatric sachets but they were causing him severe pain to the point hed cry so much he'd throw up so we lowered the dose ans stuck at it and it got better but then hes stopped eating due to his fear of choking and now hes severely constipated again to the point there was blood in his stool. I mentioned this to thr doctors for an appt and they've made him wait days.
Just want to know if anyone else's child has struggled this badly!
First time mum with health anxiety so cant stop panicking!

Photo just to lighten the topic up😫