3 Month Old Not Drinking Milk As Usual

Hi.. Recently my baby start to fuss alot when drinking milk. Usually she drinks 120ml every 2 half to 3 hours, but recently she's been cranking alot when drinking milk, have to keep trying to feed everytime more than 30min minimum to 2hrs max and still dosent want to drink. She's fussy recently too for no reason, diaper change, slept enough, tummy no issue, poop as usual.. What could be wrong? Hellllllp!!