Kitten won't stop crying?

We finally cought the stray kitten that was abandoned by it's mother today. She's only weeks old, not sure how many. She was getting along pretty well with everything til like 4 in the morning when she started meowing and meowing.. She keeps starring at me like I have something to give to her but I already gave her milk, food and snuggles.. There's a litter box too but she just hops back out when I put her in. Her meow is really loud.. Idk what to do :(