Do you offer your little one pacifier? Cause I am currently giving formula and I noticed after I feed her 3oz, an hour later she will cry again, thought she is still hungry so gave her a little more milk but she would end up vomitting out the milk. Could it be she just wants to suck on something?

Babies are very smart, they will turn away from the bottle when they are full or bite the teat to stop milk from flowing. However if you continue to encourage baby to take milk after showing these signs, then there is a tendency of you overfeeding her. Usually spit up is just reflux and it is quite normal. I assume your baby is about 2 months old. If it is vomitting then it could be that you overfeed or baby has gas in tummy. Vomitting is a projectile outlet of milk through the mouth and sometimes nose, don't confuse it with minor spit up. Babies under the age of 3 months have a strong urge to suck due to their reflex, and it may not mean that they are hungry. If you want to, you can introduce a pacifier (my baby didn't want) or allow her to suck on your knuckles for awhile.