My 6 month old baby, sucks her thumb in some duration while sleeping, does this means hungry, when i feed her while she thumb sucks, she always takes 10-20 ml milk n sleep. after half hr or 1 hr, again she started thumb sucking. what does it mean, how to recognise it is hunger or anything else. it started back from 2 months, but nowadays she does too much while sleeping, like every half or every hour .