fussy what?

Ok, is there another mom out there who can relate to a fussy baby who seems to want to be on my breast every 30 minutes (slight exageration) and seems to only cry when I am around? At four weeks, is it possible he already knows...if he cries long enough and hard enough...there will no doubt be a weakening of patience and I will finally give in? I don't want a snacker...but I don't know if that is what he's trying to do or if he really is hungry. HELP. Any advice would be greatly appreciated. Yesterday he was a gem. Today he was more like coal. I know that he was very tired towards the end of the day,but I just don't understand the eating every hour or so. Maybe he's growing. HUH? A new concept for a baby.