my cats belly is making gurgling noises. He only ate a little bit of his food and there was clear mucus on the floor when I came home.
The gurgling and mucus on the floor signify a stomach upset. Likely, this saliva and mucus was regurgitated up.
I would wait a good 12 hours before offering any kind of food, whether wanting to eat or not. Definitely leave fresh water available. Then start with a very very bland diet, like gerber baby food (chicken or turkey flavors) in a small amount. If eats ok without regurgitating it or vomiting, then give him a meal of it and see how he does. If he's easy to handle, not on other medications, and has no history of allergies to any medications, you can also give him regular pepcid ac at a dose of 0.25mg per pound of body weight 9round down if needed). Continue the bland diet for a couple of days, then gradually add back in his normal diet. Cats generally love this diet and will eat it if not eating anything else.
If at any time he really starts vomiting, the gurgling doesn't settle down, or he seems overly lethargic, he'll need a vet visit right away, to make sure he hasn't eaten something she shouldn't have, or need any antibiotics.
Don't be surprised if there is some diarrhea today- as often this gurgling is a precursor to that as well. The bland diet will help clear that up.
Good luck, let me know if I can help further.