You could try giving DS one food at a time to see if there is any reaction going on. It's hard to tell since it sounds like you mixed it up with him. Sounds like there's something he'e not fully digesting. Just make one change at at time and observe for a couple of days before you try something else.
Thank you for your feedback.
I didn't see this until just now but I freaked out the first time I saw those "worms" too! So funny!
drowning in hormones with 4 daughters and an understanding, loving hubby. also some dogs. my life is crazy and we are always learning.