So my baby is 2 months old , formula fed. She’s on similac pro total comfort , her poop is usually dark green but lately she’s been poop light yellow out of no where and the rest of the diapers will still be dark green . I haven’t changed anything like her milk or water. Is it normal ? Or should I be concerned ? She’s been fussy lately and drooling a lot . I doubt she’s teething but idk could be ...