I'm thinking she may have sore throat (not wanting to drink) that can sometimes go along with fevers and start with colds. Those can be very painful .. I'm thinking of when I've had them. It might be something she needs to be swabbed for, and could be put on meds for. I wonder if you could shine a light down her throat? If inflamed or see dots, kind of thing. Regardless, I would be calling the doc and going from there. I think I'd start there, before taking to urgent care.
The gas/bloating is likely from the constipation (just not pooping), and the pain from the gas. Try massaging her, and if she has an exersaucer or any of those little contraptions (like a jolly jumper or something like that) get her moving. That might help the BM. She may not want to if her bum hurts. Poor thing :( Would she take some pureed prunes?
But call her pediatrician and just say what you've told us here. My kiddos sometimes had fevers for a while (days) especially when they first woke up. It's the dedydration that's the concern - if she can get some in from some pureed something that will help. I think you want to avoid some foods that can bung up more, but prunes are supposed to be helpful.
good luck.