Sounds like my Junie. When she was about two weeks old, she was acting lethargic and not really eating. I inspected her and discovered her crop was filled with air/gasses (I later surmised she had some sort of blockage that was causing a yeast infection/sour crop).
I separated her from her siblings and gave her only water with electrolytes and fed her NutriDrench. I would massage the air bubbles out if her crop several times a day. I’d also give her olive oil (one eyedropper full twice a day to help work the blockage free). I was also up multiple times at night to massage the air out.
I even gave her some Monistat cream (to help battle the yeast infection since I thought the blockage was causing some sour crop issues. I would put a tiny bit on my finger - like 1/8 the size of my pinkie nail - and swipe it in her mouth).
When her crop didn’t balloon up so quick or so often, I started feeding her chick grit and gradually worked in scrambled/hard boiled eggs.
She recovered in about a week, though she was really small. Now she’s a healthy hen who doesn’t respect boundaries because her Mama Chicken gave her so much one on one attention when she was little …
Not sure if this is what’s going on with your little bean, but she might have eaten something that didn’t go through properly (I think my Junie ate a wood shaving).
Hope you figure out what’s wrong soon and your baby feels better!