As Starlight says, being in ketosis doesn't mean you won't sometimes feel hungry. You're bound to feel tempted by yummy cooking smells and want to reach for food when you're feeling stressed out - but those things are triggered more by habit than hunger.
I think having the bars can make you feel slightly hungrier, IMHO, maybe because of the effect of having something to chew. But you'll be in ketosis, nonetheless.
It does get better though. There'll come a day, probably sometime soon, when you suddenly think, "Wow, I haven't had a shake yet and it's 3pm!"