I'm breastfeeding my 4 week old baby, usually ~7 times a day. In the first feed of the day and night feeds I can hear sucking noises, but not so much in the day. My baby gets cranky between afternoon feeds, and my breasts just don't feel that full during mealtimes. She fills plenty of nappies (wet and dry), but has a chapped upper lip, and I'm worried about whether the fontanelle is dipped. Is it possible she is being underfed?